Grammar term · I'rab · The signs
Elision of nun
hadhf al-nun
حَذْف النُّون
I'rabThe signsadvanced term
In one line
Elision of the nun (حَذْف النُّون) is the dropping of the final nun, and it is the nasab and jazm marker of the five verbs.
Classical definition
وَأَمَّا حَذْفُ النُّونِ فَيَكُونُ عَلَامَةً لِلنَّصْبِ فِي الْأَفْعَالِ الْخَمْسَةِ الَّتِي رَفْعُهَا بِثَبَاتِ النُّونِ؛ وَأَمَّا الْحَذْفُ فَيَكُونُ عَلَامَةً لِلْجَزْمِ فِي الْفِعْلِ الْمُضَارِعِ الْمُعْتَلِّ الْآخِرِ، وَفِي الْأَفْعَالِ الَّتِي رَفْعُهَا بِثَبَاتِ النُّونِ.
“Elision is the marker of jazm in the present verb with a weak final letter, and in the verbs whose rafa is by retention of the nun.”
Understand it
The same missing nun serves two masters: after a nasab particle (أَن تَفْعَلُوا) and after a jazm particle (لَمْ تَفْعَلُوا) the five verbs look identical — the governor before them tells you which state struck. A vanished nun at these endings is never an error in the text; it is grammar happening.
How to spot it
Recognition test
A five-verb form without its nun — find the أَنْ / لَنْ / لَمْ / لَا that removed it.
In the Qur'an
أَحَسِبَ ٱلنَّاسُ أَن يُتْرَكُوٓا۟ أَن يَقُولُوٓا۟ ءَامَنَّا وَهُمْ لَا يُفْتَنُونَ
Al-'Ankabut 29:2 — “Do men think that they will be left alone on saying, "We believe", and that they will not be tested?”
يُتْرَكُوٓا۟ has lost its final nun because a nasab-causer entered in front of it, while يُفْتَنُونَ later in the ayah keeps its nun. The dropped letter is the marker.
Study this ayah word by word →Related terms
Common questions
How do I know the nun was dropped rather than never there?
By what stands in front of it. These verb forms carry the nun by default, so its absence is always caused — a nasab-causer or a jazm-causer has entered. If nothing has entered, the nun is there.
Next in the guideحَذْف حَرْف الْعِلَّةElision of weak letter →Updated