The sound masculine plural makes case unusually visible. Its nominative form ends in ـون, while its accusative and genitive forms end in ـين. In careful connected Modern Standard Arabic these endings are pronounced -ūna and -īna; at pause they become -ūn and -īn. The contrast survives even when the final short vowel disappears.
This plural is especially common with adjectives, participles, professions, nationalities, and nouns referring to male human beings: معلمون “teachers,” مهندسون “engineers,” مسؤولون “officials / people responsible.” Not every masculine noun forms its plural this way, so plural formation still has to be learned lexically. Here the focus is the case behavior once a sound masculine plural is available.
The case overview explains the syntactic roles that these plural endings realize.
Nominative ـون and oblique ـين
The sound masculine plural has a two-form case system:
| Case | Full connected ending | Example | Typical trigger |
|---|---|---|---|
| Nominative | ـُونَ -ūna | الْمُهَنْدِسُونَ al-muhandisūna | subject; basic nominal predicate |
| Accusative | ـِينَ -īna | الْمُهَنْدِسِينَ al-muhandisīna | direct object; after accusative governors |
| Genitive | ـِينَ -īna | الْمُهَنْدِسِينَ al-muhandisīna | after a preposition; second term of an iḍāfa |
Because accusative and genitive share ـين, they are together called oblique. The governor and role—not the spelling alone—tell you which oblique case is present.
وصل المهندسون إلى المطار.
waṣala l-muhandisūna ʾilā l-maṭār.
The engineers arrived at the airport. (Nominative subject.)
استقبلنا المهندسين في المطار.
istaqbalnā l-muhandisīna fī l-maṭār.
We welcomed the engineers at the airport. (Accusative object.)
تحدثنا مع المهندسين في المطار.
taḥaddathnā maʿa l-muhandisīna fī l-maṭār.
We spoke with the engineers at the airport. (Genitive after maʿa.)
This three-case set is the safest learning pattern. The noun is nominative because it is the subject in the first sentence, accusative because it is the object in the second, and genitive because مع governs it in the third.
Definiteness does not remove the nūn
Both definite and indefinite sound masculine plurals retain the final nūn when they are free-standing:
هناك موظفون جدد في القسم.
hunāka muwaẓẓafūna jududun fī l-qism.
There are new employees in the department.
الموظفون الجدد في اجتماع الآن.
al-muwaẓẓafūna l-jududu fī jtimāʿin al-ʾān.
The new employees are in a meeting now.
The nūn here is a written consonant and part of the plural ending; it is not tanwīn. Adding الـ therefore does not delete it. Nor does the plural itself take a doubled tanwīn mark on its nūn. In the indefinite example, definiteness is shown by the absence of the article, not by a special -un after ـون.
Adjectives agree with the plural noun in case and definiteness when they directly describe eligible human referents:
كرم المدير الموظفين المجتهدين.
karrama l-mudīru l-muwaẓẓafīna l-mujtahidīn.
The director honored the hardworking employees. (Noun and adjective are accusative.)
تعاونت مع الباحثين المشاركين في المشروع.
taʿāwantu maʿa l-bāḥithīna l-mushārikīna fī l-mashrūʿ.
I collaborated with the researchers participating in the project. (Noun and adjective are genitive.)
Do not extend this agreement blindly to non-human plurals. In standard Arabic, non-human plural nouns normally take feminine singular agreement, a separate agreement rule.
Nūn loss in construct state
When a sound masculine plural is the first term of an iḍāfa, its nūn disappears. The case-bearing long vowel remains:
| Case | Free form | Construct form |
|---|---|---|
| Nominative | مُعَلِّمُونَ muʿallimūna | مُعَلِّمُو الْمَدْرَسَةِ muʿallimū l-madrasati |
| Accusative / genitive | مُعَلِّمِينَ muʿallimīna | مُعَلِّمِي الْمَدْرَسَةِ muʿallimī l-madrasati |
شارك معلمو المدرسة في الدورة.
shāraka muʿallimū l-madrasati fī d-dawra(h).
The school's teachers took part in the course. (Nominative construct plural.)
دعونا معلمي المدرسة إلى اللقاء.
daʿawnā muʿallimī l-madrasati ʾilā l-liqāʾ.
We invited the school's teachers to the meeting. (Accusative construct plural.)
استمعنا إلى معلمي المدرسة.
istamaʿnā ʾilā muʿallimī l-madrasa(h).
We listened to the school's teachers. (Genitive construct plural.)
The last two forms look identical because the accusative and genitive are both oblique. The first is accusative as the object of دعونا; the second is genitive after إلى. The nūn deletion signals construct state, not case.
What happens at pause
Connected formal pronunciation retains the final fatḥa on nūn:
وصل الموظفون، ثم بدأ الاجتماع.
waṣala l-muwaẓẓafūna, thumma badaʾa l-ijtimāʿ.
The employees arrived, and then the meeting began. (Connected full ending before the comma.)
At utterance-final pause, only that final short a disappears. Nūn remains and receives sukūn in a fully vocalized pausal representation:
وصل الموظفون.
waṣala l-muwaẓẓafūn.
The employees arrived. (Nominative plural at pause.)
قابلت الموظفين.
qābaltu l-muwaẓẓafīn.
I met the employees. (Accusative plural at pause.)
Unlike a singular noun whose final short case vowel may vanish at pause, the sound masculine plural still contrasts -ūn with -īn. Pause hides the final inflectional a, not the nominative–oblique distinction.
Reading unvocalized text
Unvocalized Arabic normally preserves the و versus ي, so this plural often gives readers more case information than a singular triptote. Still, context remains essential: المهندسين could be accusative or genitive, and معلمي المدرسة could be two words in an iḍāfa or, in another context, involve an attached first-person suffix on a singular form. Syntax resolves the intended analysis.
Object-fronting makes the role of the endings especially clear (formal):
كرم الموظفين المديرون في الحفل.
karrama l-muwaẓẓafīna l-mudīrūna fī l-ḥafl.
It was the employees whom the directors honored at the ceremony. (Marked object-first order.)
Here الموظفين is accusative even though it comes first, while المديرون is nominative subject. The singular verb before the overt plural subject is the standard verb-initial agreement pattern.
Visible, estimated, and local case
This plural normally has visible iʿrāb because و and ي display the nominative–oblique opposition. Elsewhere, Arabic can assign estimated case when phonology prevents the normal ending from surfacing, or local case to an indeclinable expression. Pause does not change visible case into local case: الموظفونْ is still a visibly nominative sound masculine plural even though its final fatḥa is not pronounced.
Common Mistakes
1. Using ـين for a nominative subject.
❌ وصل الموظفين مبكرا.
Incorrect: the employees are the subject, so the sound masculine plural must be nominative.
✅ وصل الموظفون مبكرا.
waṣala l-muwaẓẓafūna mubakkirā.
The employees arrived early.
2. Keeping nūn on the first term of an iḍāfa.
❌ حضر معلمون المدرسة.
Incorrect for ‘the school's teachers’: the construct plural must lose nūn.
✅ حضر معلمو المدرسة.
ḥaḍara muʿallimū l-madrasa(h).
The school's teachers attended.
3. Deleting nūn merely because the word is at pause.
❌ وصل الموظفو.
Incorrect: pause removes final -a but keeps nūn.
✅ وصل الموظفون.
waṣala l-muwaẓẓafūn.
The employees arrived.
4. Assuming the first noun after the verb must be the subject.
❌ كرم الموظفون المديرين.
Incorrect for the intended object-first reading: these forms reverse the roles.
✅ كرم الموظفين المديرون.
karrama l-muwaẓẓafīna l-mudīrūn.
It was the employees whom the directors honored.
5. Treating every fatḥa as accusative or every final vowel as noun case.
❌ لن يحضر الموظفين.
Incorrect: lan governs the verb's mood; the following subject still requires nominative case.
✅ لن يحضر الموظفون.
lan yaḥḍura l-muwaẓẓafūn.
The employees will not attend.
Remember too that a fatḥa on an indefinite diptote after a preposition marks genitive, not accusative. The identity of the form and its governor matter more than the visual shape of one vowel.
❌ اجتمعنا في مكاتب حديثة.
Incorrect: indefinite diptote makātib does not take kasra after the preposition.
✅ اجتمعنا في مكاتب حديثة.
ijtamaʿnā fī makātiba ḥadītha(h).
We met in modern offices. (Makātiba is genitive despite its fatḥa.)
Key Takeaways
Use ـونَ for the nominative sound masculine plural and ـينَ for both accusative and genitive. The written nūn is part of the plural ending, so the article does not remove it; construct state does. At pause, pronounce -ūn or -īn, preserving both nūn and the case contrast. Throughout, identify the governor and syntactic role before choosing an ending.
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- Case on the DualA2 — Use the Arabic dual in nominative and oblique cases, including construct-state nūn loss, adjective agreement, and pausal pronunciation.
- Case on the Sound Feminine PluralA2 — Learn why sound feminine plurals use -ātu in the nominative but -āti in both accusative and genitive contexts.
- What Iʿrāb DoesA1 — Understand how nominative, accusative, and genitive case signal a noun phrase's role even when writing or pause hides the ending.