Arabic Noun Cases (I‘rab)

In Brief

In formal Arabic, a noun’s final sound can show its job in the sentence. The basic endings are -u for the nominative (مرفوع), -a for the accusative (منصوب), and -i for the genitive (مجرور): الطالبُ، الطالبَ، الطالبِ. Indefinite nouns normally add tanwin, giving -un, -an, -in.

Overview

A noun is a word for a person, place, thing, or idea, such as “student,” “city,” or “freedom.” In formal Arabic, nouns and adjectives can change their endings according to their grammatical role. This system is called الإعراب (al-i‘rāb, grammatical inflection), and each form is called a case. A case is simply a form that helps show what a word is doing in its sentence.

Arabic has three noun cases. The nominative usually marks the subject—the person or thing performing an action—and the two main parts of a basic nominal sentence. The accusative commonly marks the direct object—the person or thing directly affected by an action. The genitive appears after a preposition and on the possessor in an idafa construction. You meet this core system at A2, but case also supports many later topics.

English nouns usually do not change this way: “the student” has the same form in “the student arrived” and “I saw the student.” English preserves a similar contrast mainly in pronouns such as “he,” “him,” and “his.” Arabic uses endings on ordinary nouns and their adjectives, although those short vowels are often not written and are usually absent from everyday dialect speech.

How It Works

The three basic endings

Start with a regular singular noun that can take all three endings. Traditional Arabic grammar calls such a noun مُنْصَرِف; “fully declinable” is a useful plain-English description.

Case	Arabic term	Definite form	Indefinite form	Core beginner use
Nominative	مرفوع (marfū‘)	الطالبُ aṭ-ṭālibu	طالبٌ ṭālibun	Subject; subject and predicate of a basic nominal sentence
Accusative	منصوب (manṣūb)	الطالبَ aṭ-ṭāliba	طالبًا ṭāliban	Direct object
Genitive	مجرور (majrūr)	الطالبِ aṭ-ṭālibi	طالبٍ ṭālibin	After a preposition; possessor in an idafa

The marks ُ َ ِ are respectively ḍamma, fatḥa, and kasra. They are short-vowel signs placed above or below the final consonant. In unvowelled text, all three definite forms are normally written simply الطالب, so you must infer the case from the sentence structure.

Definite endings and tanwin

A noun with the definite article الـ takes one short case vowel:

• الكتابُ al-kitābu — nominative
• الكتابَ al-kitāba — accusative
• الكتابِ al-kitābi — genitive

A regular indefinite noun normally takes تنوين (tanwīn), a doubled vowel sign that adds an n sound:

• كتابٌ kitābun — nominative -un
• كتابًا kitāban — accusative -an
• كتابٍ kitābin — genitive -in

Accusative -an is usually written with an extra ا, as in كتابًا. The spelling has exceptions: after ة, for example, write مدرسةً, not an extra alif after the ة. You do not combine الـ and tanwin: الكتابٌ is impossible.

When to use the nominative

The nominative is the default case for several central sentence roles:

1. The subject of a verb—the person or thing that performs the action:
   • جاء الطالبُ. — “The student came.”
2. The subject and predicate of a basic nominal sentence. A predicate says what the subject is or is like:
   • الكتابُ جديدٌ. — “The book is new.”
3. The doer in a passive sentence, traditionally called the نائب الفاعل:
   • فُتِحَ البابُ. — “The door was opened.”

For the A2 rule, remember: the doer is normally nominative, and both main parts of a simple present-time “X is Y” sentence are normally nominative.

When to use the accusative

The most important A2 use is the direct object—who or what directly receives the action:

• رأيتُ الطالبَ. — “I saw the student.”
• اشتريتُ كتابًا. — “I bought a book.”

The accusative has many other uses. It can mark time, manner, circumstance, specification, and certain predicates:

• سافرتُ صباحًا. — “I travelled in the morning.”
• عاد الطفلُ سعيدًا. — “The child returned happy.”
• كان الجوُّ جميلًا. — “The weather was beautiful.”

You do not need to master all these patterns at A2. First learn to identify direct objects; later, learn each additional accusative construction as its own pattern.

When to use the genitive

The genitive has two essential triggers.

1. After a preposition. A preposition is a short word such as “in,” “from,” or “to” that links a noun to the rest of the sentence.

• في البيتِ — “in the house”
• من المطارِ — “from the airport”
• إلى المدينةِ — “to the city”
• بالطالبِ — “by/with the student”

Single-letter prepositions such as بـ “with/by” and لـ “for/to” attach directly to the following word.

2. As the second noun in an idafa. An إضافة (iḍāfa) is a noun-to-noun construction often corresponding to English “of” or possessive ’s:

• كتابُ الطالبِ — “the student’s book”
• بابُ البيتِ — “the door of the house”

The second noun is genitive. The first noun’s case depends on its own role in the larger sentence: compare كتابُ الطالبِ جديدٌ (“The student’s book is new”) with قرأتُ كتابَ الطالبِ (“I read the student’s book”).

Adjectives follow their nouns

An adjective—a word that describes a noun—agrees with that noun in case as well as in definiteness, gender, and number. This is why both words change in these phrases:

Case	Definite phrase	Indefinite phrase
Nominative	الكتابُ الجديدُ	كتابٌ جديدٌ
Accusative	الكتابَ الجديدَ	كتابًا جديدًا
Genitive	الكتابِ الجديدِ	كتابٍ جديدٍ

Do not choose an adjective ending independently. Find the case of the noun first, then copy that case onto its agreeing adjective.

Number changes the visible case marker

The labels “-u, -a, -i” describe the basic singular pattern, but duals and regular plurals use longer endings.

Noun type	Nominative	Accusative	Genitive
Singular, regular	معلّمٌ	معلّمًا	معلّمٍ
Dual	معلّمانِ	معلّمَيْنِ	معلّمَيْنِ
Sound masculine plural	معلّمونَ	معلّمينَ	معلّمينَ
Sound feminine plural	معلّماتٌ	معلّماتٍ	معلّماتٍ

The dual means exactly two: nominative -āni, but accusative and genitive -ayni. The sound masculine plural uses -ūna in the nominative and -īna in both other cases. A particularly important exception to the simple vowel mnemonic is the sound feminine plural: its accusative has kasra, the same visible ending as its genitive.

Examples in Context

The following examples show case as part of complete sentences. The Arabic includes the endings that matter, even though ordinary unvowelled writing may omit them.

Arabic	English	Note
جاء الطالبُ.	The student came.	الطالبُ is the subject, so it is nominative.
رأيتُ الطالبَ.	I saw the student.	الطالبَ is the direct object, so it is accusative.
مررتُ بالطالبِ.	I passed by the student.	بـ requires the genitive.
كتابٌ جديدٌ على المكتبِ.	A new book is on the desk.	The indefinite subject and its adjective are nominative; المكتبِ follows على.
الجوُّ جميلٌ اليومَ.	The weather is beautiful today.	Both parts of the nominal sentence are nominative.
اشتريتُ سيارةً صغيرةً.	I bought a small car.	The object and its adjective are accusative.
سافرنا إلى مدينةٍ قديمةٍ.	We travelled to an old city.	مدينةٍ follows إلى, and its adjective matches it.
هذا مفتاحُ السيارةِ.	This is the car key.	السيارةِ is the second noun of the idafa.
وصلَ القطارُ صباحًا.	The train arrived in the morning.	The subject is nominative; the time expression is accusative.
حضرَ الطالبانِ مبكرًا.	The two students arrived early.	A dual subject takes nominative -āni.
قابلتُ المعلّمَيْنِ.	I met the two teachers.	A dual object takes accusative -ayni.
عادَ المعلّمونَ إلى المدرسةِ.	The teachers returned to the school.	The sound masculine plural subject takes -ūna.
شاهدتُ المعلّماتِ في المكتبةِ.	I saw the female teachers in the library.	The sound feminine plural object has kasra in the accusative.
إنّ الطريقَ طويلٌ.	The road is indeed long.	After إنّ, the subject is accusative but the predicate remains nominative.
كانَتِ الحديقةُ هادئةً.	The garden was quiet.	With كان, the subject is nominative and the predicate is accusative.

Common Mistakes

Giving the subject an accusative ending

• Wrong: جاء الطالبَ.
• Right: جاء الطالبُ.
• Why: الطالب performs the action “came,” so it is the nominative subject.

Leaving a direct object nominative

• Wrong: رأيتُ الطالبُ.
• Right: رأيتُ الطالبَ.
• Why: The student is the person seen—the direct object—so the noun is accusative.

Forgetting that prepositions govern the genitive

• Wrong: في البيتُ
• Right: في البيتِ
• Why: A noun after في must be genitive. Learn each common preposition together with this effect.

Letting the adjective disagree

• Wrong: كتابٌ جديدٍ
• Right: كتابٌ جديدٌ
• Why: The adjective describes a nominative noun, so it must also be nominative. Agreement applies whether the phrase is definite or indefinite.

Combining the definite article with tanwin

• Wrong: الكتابٌ
• Right: الكتابُ
• Why: A noun made definite with الـ does not take tanwin. Use one case vowel instead.

Forcing fatḥa onto every accusative plural

• Wrong: شاهدتُ معلّماتًا.
• Right: شاهدتُ معلّماتٍ.
• Why: The sound feminine plural marks both accusative and genitive with kasra. The word’s role is still accusative even though its visible sign is not fatḥa.

Usage Notes

Case endings belong primarily to Modern Standard Arabic and Classical Arabic. They matter in carefully edited texts, formal speeches, news reading, religious texts, poetry, and grammar study. Most everyday Arabic dialects do not productively use the full three-case system, so a speaker may say the same noun form regardless of its sentence role.

Even in formal Arabic, short vowels are normally omitted in ordinary writing. Readers determine case from syntax and meaning. Fully vowelled children’s books, teaching materials, dictionaries, and Qur’anic editions make the endings more visible.

Pronunciation also depends on position. In connected speech, a careful reader may pronounce the case ending because another word follows. At a pause, especially at the end of a sentence, the final short vowel or tanwin is commonly not pronounced: جاء الطالبُ may end aloud as jā’a ṭ-ṭālib. This pause form does not mean that the noun has lost its grammatical case.

For learners, the practical goal is not to attach a loud ending to every word in every conversation. Learn to recognise the grammatical relationships first. Then practise endings in short, fully vowelled formal sentences, where they are useful and expected.

Beyond the Basics

You do not need to master the patterns in this section at A2, but they explain forms you will meet later.

Diptotes

Some nouns are diptotes (ممنوع من الصرف), meaning that they use a reduced case pattern. They do not normally take tanwin, and their indefinite genitive is marked with fatḥa rather than kasra:

• مساجدُ كثيرةٌ — “many mosques” (nominative)
• زرتُ مساجدَ كثيرةً — “I visited many mosques” (accusative)
• صلّيتُ في مساجدَ كثيرةٍ — “I prayed in many mosques” (genitive after a preposition, but marked with fatḥa)

When a diptote has الـ or is the first term of an idafa, it normally uses kasra in the genitive: في المساجدِ. Certain broken-plural patterns, proper names, and adjective patterns are diptotes; it is best to learn the common categories separately rather than guess.

Special noun classes

The “five nouns,” including أب “father” and أخ “brother” in particular constructions, can mark case with long vowels:

• جاء أبوكَ. — “Your father came.”
• رأيتُ أباكَ. — “I saw your father.”
• تحدّثتُ مع أبيكَ. — “I spoke with your father.”

Nouns ending in ى, such as الفتى “the young man,” can keep the same written shape in all three cases because the short ending cannot appear normally on the final alif. Traditional analysis still assigns them a case according to their role.

Particles and verbs can reassign case

A basic nominal sentence has a nominative subject and predicate, but certain words change that pattern. إنّ and its related particles make their subject accusative while leaving the predicate nominative: إنّ الكتابَ مفيدٌ. كان and related verbs keep their subject nominative but make their predicate accusative: كان الكتابُ مفيدًا.

Many advanced accusative roles also build on this case system: حال describes someone’s state during an action, تمييز clarifies a quantity or quality, and المفعول المطلق adds emphasis or specifies how an action happens. The case is familiar, but each construction has its own meaning and rules.

Case and word order

Visible case can help identify roles when word order changes. Compare قابلَ المعلّمُ الطالبَ (“The teacher met the student”) with قابلَ المعلّمَ الطالبُ (“The student met the teacher”). In fully vowelled formal Arabic, the endings distinguish subject from object. In ordinary unvowelled text, writers rely heavily on normal word order, context, and avoidance of ambiguity; case does not make every possible rearrangement equally natural.

Practice Tips

1. Use a three-sentence frame. Take one noun and say جاءَ... (“…came”), رأيتُ... (“I saw…”), and مررتُ بـ... (“I passed by…”). For example: المعلّمُ، المعلّمَ، بالمعلّمِ. This ties each ending to a sentence role rather than to an isolated label.
2. Mark roles before endings. In a short vowelled sentence, underline the subject, circle the direct object, and box every preposition. Only then choose -u, -a, or -i. Add matching endings to adjectives last.
3. Read twice. First read a formal sentence in the natural pause style. Then read it slowly in connected speech, pronouncing the case endings. This keeps grammar practice separate from the mistaken idea that every ending must always be audible.

Related Concepts

• Prerequisite: Nominal Sentences — introduces the subject–predicate structure whose two basic parts are nominative.
• Next step: Genitive Construction (Idafa) — uses the genitive for the second noun in a possession or classification phrase.
• Next step: إنّ and Sisters — shows how particles make the subject of a nominal sentence accusative.
• Later use: Circumstantial Clauses (Hal) — develops an important descriptive use of the accusative.
• Later use: Specification (Tamyiz) — uses an accusative noun to clarify quantities and comparisons.
• Later use: Vocative (Nida) — applies special case rules when directly addressing someone.
• Later use: Emphasis (Tawkid) — includes emphatic words that follow the case of the expression they reinforce.
• Later use: Absolute Object (Maf‘ul Mutlaq) — extends the accusative to verbal nouns used for emphasis or manner.