Prohibitive لا with the Jussive | Arabic (Modern Standard) Grammar

Arabic uses لا الناهية + jussive imperfect for a negative command: لا تفتحْ الباب “Do not open the door.” This is different from ordinary negative لا, which denies a present habit or general fact and leaves the imperfect indicative: لا يفتحُ المتجر يوم الجمعة “The shop does not open on Friday.”

The two particles are written alike, and ordinary unvocalized text can hide the difference between تكتبْ and تكتبُ. Meaning, addressee, and morphology work together. In the five verbs, prohibition deletes indicative nūn; with final-weak verbs it deletes the weak letter; feminine-plural nūn remains because it marks agreement.

The positive second-person command is treated on the basic imperative page. Prohibitive لا keeps the imperfect agreement prefix and therefore also extends naturally to third-person directives.

All second-person forms

Regular Form I كَتَبَ / يَكْتُبُ “write,” root ك ت ب, provides the complete second-person map:

Addressee	Indicative imperfect	Prohibitive jussive	Change
أنتَ	تَكْتُبُ	لَا تَكْتُبْ	final -u → sukūn
أنتِ	تَكْتُبِينَ	لَا تَكْتُبِي	nūn deleted
أنتما	تَكْتُبَانِ	لَا تَكْتُبَا	nūn deleted
أنتم	تَكْتُبُونَ	لَا تَكْتُبُوا	nūn deleted
أنتنّ	تَكْتُبْنَ	لَا تَكْتُبْنَ	agreement nūn remains

لا تفتح المرفق قبل فحصه ببرنامج الحماية.

lā taftaḥi l-murfaqa qabla faḥṣihi bi-barnāmaji l-ḥimāya(h).

Do not open the attachment before scanning it with the security software. (Addressing one man.)

Underlying تفتحْ gains support i before the article. It remains jussive.

لا تكتبي كلمة المرور في هذه الرسالة.

lā taktubī kalimata l-murūri fī hādhihi r-risāla(h).

Do not write the password in this message. (Addressing one woman.)

لا تتعجلا في توقيع العقد قبل قراءة الملحق.

lā tataʿajjalā fī tawqīʿi l-ʿaqdi qabla qirāʾati l-mulḥaq.

Do not rush to sign the contract before reading the appendix. (Addressing two people.)

لا تغادروا القاعة حتى ينتهي التصويت.

lā tughādirū l-qāʿata ḥattā yantahiya t-taṣwīt.

Do not leave the hall until the vote is over. (Addressing a masculine or mixed group.)

لا تتأخرن عن جلسة التدريب يا موظفات.

lā tataʾakhkharna ʿan jalsati t-tadrībi yā muwaẓẓafāt.

Do not be late for the training session, employees. (Addressing an all-female group.)

The last نَ is nūn al-niswa. Removing it would erase feminine-plural agreement rather than mark jussive mood.

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For second-person prohibitions, begin from the second-person imperfect jussive, not from the positive imperative. This preserves the crucial تـ prefix in every cell.

Third-person prohibitions and directives

Formal MSA can prohibit an action by a third person: “Let no one enter,” “The applicants must not send...” This is common in regulations, notices, legal drafting, and elevated directives (formal).

The same jussive system extends across the third person. These forms often translate most naturally with “is not to,” “must not,” or “let ... not,” rather than a literal English imperative:

Person	Prohibitive form	Typical force
he / one masculine subject	لَا يَكْتُبْ	he is not to write
she / one feminine subject	لَا تَكْتُبْ	she is not to write
two masculine subjects	لَا يَكْتُبَا	the two are not to write
two feminine subjects	لَا تَكْتُبَا	the two are not to write
masculine or mixed plural	لَا يَكْتُبُوا	they are not to write
feminine plural	لَا يَكْتُبْنَ	they are not to write

لا يدخل أحد إلى المختبر من دون تصريح.

lā yadkhul ʾaḥadun ʾilā l-mukhtabari min dūni taṣrīḥ.

No one is to enter the laboratory without authorization. (Formal directive.)

لا يرسل الموظفون البيانات إلى أي عنوان شخصي.

lā yursili l-muwaẓẓafūna l-bayānāti ʾilā ʾayyi ʿunwānin shakhṣiyy.

The employees must not send the data to any personal address. (Formal policy.)

The preposed third-person verb is singular before the explicit human plural subject. Underlying يرسلْ gains connected i before the article.

لا تتجاوز المركبات السرعة المحددة داخل الموقع.

lā tatajāwazi l-markabātu s-surʿata l-muḥaddadata dākhila l-mawqiʿ.

Vehicles must not exceed the specified speed on the site. (Formal regulation.)

Nonhuman plural المركبات takes feminine-singular تتجاوزْ in VSO. The jussive ending and agreement rule are independent.

These third-person prohibitions can sound official. In neutral descriptive prose, indicative negation may be intended instead.

Prohibition versus ordinary negation

Compare identical-looking unvocalized strings with different force:

لا يرسل سامر الملفات من هاتفه الشخصي.

lā yursilu sāmiru l-milaffāti min hātifihi sh-shakhṣiyy.

Samer does not send files from his personal phone. (Ordinary indicative negation.)

لا يرسل سامر الملفات قبل موافقة المديرة.

lā yursil sāmiru l-milaffāti qabla muwāfaqati l-mudīra(h).

Samer is not to send the files before the director approves. (Formal prohibition.)

The first reports a habit and has يرسلُ. The second issues a directive and has يرسلْ. English also distinguishes “does not” from “must not,” but Arabic encodes the contrast directly in mood when endings are pronounced.

Future لن is a third construction, not another way to form a prohibition. It denies or predicts a future event and governs the subjunctive:

لن تفتح الإدارة الفرع الجديد هذا الشهر.

lan taftaḥa l-ʾidāratu l-farʿa l-jadīda hādhā sh-shahr.

The administration will not open the new branch this month. (Future negation, not a command.)

Compare لا تفتحْ “do not open” with لن تفتحَ “you will not open.” The first is jussive and directive; the second is subjunctive and future-negative.

الموظفون لا يرسلون الفواتير يوم الجمعة.

ʾal-muwaẓẓafūna lā yursilūna l-fawātīra yawma l-jumuʿa(h).

The employees do not send invoices on Fridays. (Descriptive habit.)

Subject-first indicative يرسلونَ retains nūn. Prohibitive لا ترسلوا addressed to those employees would delete it.

Weak-final and geminate prohibitions

Final-weak verbs delete their weak letter in the jussive.

The relevant jussive shape must come from verified principal parts, not from an English gloss:

Principal parts	Class	Prohibition to one man
دَعَا / يَدْعُو, root د ع و	final-wāw	لَا تَدْعُ
رَمَى / يَرْمِي, root ر م ي	final-yāʾ	لَا تَرْمِ
سَعَى / يَسْعَى, root س ع ي	final-alif	لَا تَسْعَ
قَالَ / يَقُولُ, root ق و ل	hollow-wāw	لَا تَقُلْ
رَدَّ / يَرُدُّ, root ر د د	geminate	لَا تَرُدَّ

لا تدع أي شخص إلى المبنى قبل التحقق من هويته.

lā tadʿu ʾayya shakhṣin ʾilā l-mabnā qabla t-taḥaqquqi min huwiyyatih.

Do not invite anyone into the building before verifying their identity. (Addressing one man.)

Form I دَعَا / يَدْعُو, root د ع و, becomes jussive تدعُ, with final wāw deleted.

لا تمش وحدك في هذا الجزء من الطريق ليلا.

lā tamshi waḥdaka fī hādhā l-juzʾi mina ṭ-ṭarīqi laylan.

Do not walk alone on this part of the road at night. (Addressing one man.)

Final-yāʾ مَشَى / يَمْشِي, root م ش ي, becomes تمشِ.

Geminate رَدَّ / يَرُدُّ, root ر د د, commonly uses contracted jussive تردَّ in connected speech, alongside expanded تردُدْ.

لا ترد على الرسالة قبل التأكد من عنوان المرسل.

lā tarudda ʿalā r-risālati qabla t-taʾakkudi min ʿunwāni l-mursil.

Do not reply to the message before checking the sender's address. (Addressing one man.)

The fatḥa that releases the geminate cluster does not make تردَّ subjunctive; prohibitive لا establishes jussive syntax. Before feminine-plural nūn, the geminate unfolds:

لا ترددن على المكالمات المجهولة من هواتفكن الشخصية.

lā tardudna ʿalā l-mukālamāti l-majhūlati min hawātifikunna sh-shakhṣiyya(h).

Do not answer unknown calls from your personal phones. (Addressing an all-female group.)

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When the displayed form is ambiguous, test speech act first: a factual denial takes indicative لا; an instruction not to act takes prohibitive لا + jussive.

Common Mistakes

Putting لا before a positive imperative

❌ لا اكتب اسمك هنا.

Incorrect — prohibitive لا takes the jussive imperfect تكتبْ, not the positive imperative اكتبْ.

✅ لا تكتب اسمك في الجزء المخصص للموظف.

lā taktubi smaka fī l-juzʾi l-mukhaṣṣaṣi lil-muwaẓẓaf.

Do not write your name in the section reserved for the employee.

Pronouncing a prohibition as indicative

❌ لا تفتح الرابط قبل التحقق منه.

lā taftaḥu r-rābiṭa qabla t-taḥaqquqi minh

Incorrect pronunciation for a command — prohibitive لا requires jussive تفتحْ.

✅ لا تفتح الرابط قبل قراءة عنوانه كاملا.

lā taftaḥi r-rābiṭa qabla qirāʾati ʿunwānihi kāmilan.

Do not open the link before reading its full address. (Addressing one man.)

Making ordinary descriptive negation jussive

❌ لا يعمل المتجر يوم الأحد عادة.

lā yaʿmali l-matjaru yawma l-ʾaḥad

Incorrect pronunciation for a habitual fact — ordinary negative لا requires indicative يعملُ.

✅ لا يعمل المتجر يوم الأحد خلال الشتاء.

lā yaʿmalu l-matjaru yawma l-ʾaḥadi khilāla sh-shitāʾ.

The shop does not operate on Sundays during winter.

Retaining indicative nūn in a prohibition

❌ لا ترسلون النسخة قبل المراجعة.

Incorrect — a prohibition to a masculine or mixed group requires ترسلوا without nūn.

✅ لا ترسلوا النسخة قبل مراجعة جميع الأسماء.

lā tursilū n-nuskhata qabla murājaʿati jamīʿi l-ʾasmāʾ.

Do not send the copy before checking all the names. (Addressing a masculine or mixed group.)

Replacing feminine-plural agreement with masculine plural

❌ لا تتأخروا يا موظفات عن الموعد.

Incorrect — an all-female group requires لا تتأخرن, not masculine-plural تتأخروا.

✅ لا تتأخرن يا موظفات عن موعد الحافلة.

lā tataʾakhkharna yā muwaẓẓafātu ʿan mawʿidi l-ḥāfila(h).

Do not be late for the bus, employees. (Addressing an all-female group.)

Keeping a final weak letter

❌ لا تدعو أحدا إلى الغرفة الآن.

Incorrect for a command to one man — دعا / يدعو loses wāw in jussive تدعُ.

✅ لا تدع أحدا إلى الغرفة قبل انتهاء الفحص.

lā tadʿu ʾaḥadan ʾilā l-ghurfati qabla ntihāʾi l-faḥṣ.

Do not invite anyone into the room before the inspection ends. (Addressing one man.)

Key Takeaways

Prohibitive لا governs the jussive and creates a negative command or directive.
All five second-person cells preserve their gender and number distinctions; feminine-plural nūn remains.
Third-person prohibitions are productive in formal rules, policies, and notices.
Ordinary negative لا states a fact and leaves the imperfect indicative.
Final-weak verbs delete the weak letter; contracted geminates can use a cluster-breaking fatḥa while remaining jussive.

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