First term

The first term in iḍāfah has the following characteristics:^[7]

• It must be in the construct state: that is, it does not have the definite article or any nunation (any final -n), or any possessive pronoun suffix.
  • When using a pronunciation that generally omits cases (’i‘rāb), the ة (tā’ marbūṭah) of any term in the construct state must always be pronounced with a -t (after /a/) when spoken, e.g. خالة أَحْمَد khālat ’aḥmad "Ahmad's aunt".
• It can be in any case: this is determined by the grammatical role of the first term in the sentence where it occurs.

Second term

The second term in iḍāfah has the following characteristics when it is a noun:^[8]

• It must be in the genitive case.
• It is marked as definite (with the definitive article) or indefinite (with nunation, in those varieties of Arabic that use it), and can take a possessive pronoun suffix. The definiteness or indefiniteness of the second term determines the definiteness of the entire idāfa phrase.

Three or more terms

iḍāfah constructions of multiple terms are possible, and in such cases, all but the final term are in the construct state, and all but the first member are in the genitive case. For example: سَرْقةُ جَوازِ سَفَرِ أِحَدِ اللاعِبِينَ sarqatu jawāzi safari ’aḥadi l-lā‘ibīna "the theft of the passport [literally "license of journey"] of one of the athletes".^[9]

Modifying the first term

An adjective modifying the first noun appears at the end of the iḍāfah and agrees with the noun it describes in number, gender, case, and definiteness (the latter of which is determined by the last noun of the iḍāfah).^[12]

Modifying the last term

An adjective modifying the last term appears at the end of the iḍāfah and agrees with the noun it describes in number, gender, definiteness, and case (which is always genitive).

Modifying both terms

If both terms in the idāfa are modified, the adjective modifying the last term is set closest to the idāfa, and the adjective modifying the first term is set further away.^[13] For example:

Variant forms

For all but the first person singular, the same forms are used regardless of the part of speech of the word attached to. In the third person masculine singular, -hu occurs after the vowels u or a (-a, -ā, -u, -ū, -aw), while -hi occurs after i or y (-i, -ī, -ay). The same alternation occurs in the third person dual and plural.

صَدِيقَتُهَا ṣadīqatu-hā "her friend"

صَدِيقَتُهَا الجَدِيدةُ ṣadīqatu-hā l-jadīdatu "her new friend"

صَدِيقةٌ لَهَا ṣadīqatun la-hā "a friend of hers"

صَدِيقةٌ جَدِيدةٌ لَهَا ṣadīqatun jadīdatun la-hā "a new friend of hers"

In the first person singular, however, the situation is more complicated; -ī/-ya "my" is attached to nouns. In the latter case, -ya is attached to nouns whose construct state ends in a long vowel or diphthong (e.g. in the sound masculine plural and the dual), while -ī is attached to nouns whose construct state ends in a short vowel, in which case that vowel is elided (e.g. in the sound feminine plural, as well as the singular and broken plural of most nouns). Furthermore, -ū of the masculine sound plural is assimilated to -ī before -ya (presumably, -aw of masculine defective -an plurals is similarly assimilated to -ay). Examples:

• From ‏كِتابٌ‎ kitāb "book", pl ‏كُتُبٌ‎ kutub (most of nouns in general).

• From ‏كَلِمةٌ‎ kalimah "word" (nouns ending on ة‎), pl ‏كَلِمَات‎‎ or ‏كَلِم‎‎.

• From ‏دُنْيَا‎ dunyā "world"; ‏مُسْتَشْفًى‎ mustashfan "hospital" (nouns ending on ـَا ـَى ـًى).

• From nom. dual ‏مُعَلِّمانَ‎ mu‘allimān "teachers", acc./gen. dual مُعَلِّمَينَ mu‘allimayn (dual nouns)

• From nom. pl. مُعَلِّمُونَ mu‘allimūn "teachers", acc./gen. pl. مُعَلِّمِينَ mu‘allimīn (regular plural ـُون nouns)

• From pl. ‏مُصْطَفَوْنَ‎ muṣṭafawn "chosen" (regular plural ـَوْن nouns)

• From ‏قاضٍ‎ qāḍin "judge" (active participle nouns ending on ـٍ as nominative)

• From ‏أَبٌ‎ ab "father", long construct form أَبُو abū (long construct nouns)

• From any nouns ending on ـُو -ū, ـَو -aw or ـِي -ī (more commonly loanwords).

• From any nouns ending on ـَي -ay (more commonly loanwords).

Pronominal nouns in most of Arabic dialects

• From ‏كِتابٌ‎ kitāb "book", pl ‏كُتُبٌ‎ kutub (most of nouns in general).

• From ‏كِلْمة‎ kilma "word" (nouns ending on ة).

• From ‏دُنْيا‎ dunyā "world"

• From ‏أَب‎ ab "father"