Nahw · syntaxVerb class (in syntax)core term89+ in the Qur'an
Also written: Laysa · Is not · Negating the nominal sentence
In one line
The defective verb “is not” — it negates a nominal sentence: the subject stays in raf', the khabar goes to nasb.
Classical definition
لَيْسَ فِعْلٌ مَاضٍ جَامِدٌ يُفِيدُ نَفْيَ الْجُمْلَةِ الاسْمِيَّةِ، يَرْفَعُ الاسْمَ وَيَنْصِبُ الْخَبَرَ.
“Laysa is a non-conjugating (jamid) past-form verb that negates the nominal sentence: it keeps the noun in raf' and puts the khabar into nasb.”
(بتصرف من النحو الوافي)
Key words in the Arabic
جَامِدnon-conjugating — it has no mudari' or amr
Understand it
لَيْسَ is the first of كَانَ's sisters a student meets, and the standard way to say “is not” about a nominal sentence: زَيْدٌ عَالِمٌ (“Zayd is a scholar”) becomes لَيْسَ زَيْدٌ عَالِمًا — the subject keeps raf', the khabar takes nasb. Because لَيْسَ is a verb, it agrees in gender: لَيْسَتْ زَيْنَبُ ذَكِيَّةً. Adding بِ to the khabar makes the negation emphatic — and pulls the khabar into jarr: مَا حَامِدٌ بِشَيْخٍ, “Hamid is certainly no scholar” (the same بِ pattern follows لَيْسَ). It appears 74 times in the Quran as لَيْسَ, with لَيْسَتْ three times.
How to spot it
Recognition test
لَيْسَ or لَيْسَتْ at the head of (or inside) a nominal sentence: expect the khabar in nasb — or in jarr after the emphasising بِ.
In the Qur'an
لَيْسَ كَمِثْلِهِ شَيْءٌ
Ash-Shura 42:11 — “There is nothing like unto Him”
لَيْسَ negates; the khabar كَمِثْلِهِ (a jarr phrase) is brought forward because the subject is indefinite; شَيْءٌ is the ism of laysa, in raf'.
Forms it takes
لَيْسَلَيْسَتْلَسْتُلَسْتُمْلَيْسُوا
Don't confuse it with
مَا negates a nominal sentence the same way — khabar to nasb — but it is a particle and never changes form. لَيْسَ is a verb and must agree in gender with its subject.
Related terms
▶ Watch the lesson
From the free course The Language of Quran — Easier than English (Book 1) (LoQ1), taught by Ustad Muhammad Arjan Ali.
Common questions
Why is laysa called a “defective” verb?
Fi'l naqis does not mean broken — it means incomplete on its own. لَيْسَ sets up a negation but always needs a khabar to complete the picture, and being jamid it never conjugates into a mudari' or amr.
Domain: Nahw · Category: Verb class (in syntax) · Frequency in the Qur'an: 89 · Source: بتصرف من النحو الوافي, cross-checked against the Quranic corpus · Reviewed by Ustad M. Arjan Ali