What is the stand-in doer (na'ib al-fa'il)?
In one line
Classical definition
Understand it
Sometimes the doer is not mentioned at all — because it is unknown, or because the speaker has no reason to name it. The verb then changes its shape, and the word that would have been the object steps into the empty place.
Compare the two. ضَرَبَ عَمْرٌو زَيْدًا (daraba 'amrun zaydan), 'Amr struck Zayd — زَيْدًا is the object, in nasab. Now drop the doer: ضُرِبَ زَيْدٌ (duriba zaydun), Zayd was struck. The same word is now مَرْفُوع, because it is now filling the doer's role.
Where it sits
Name the doer and you have a fa'il with an object in nasab. Leave the doer unnamed and the object moves up into rafa as the na'ib al-fa'il.
The verb marks the change on itself. In the past tense the first letter takes a damma and the letter before the last takes a kasra — ضَرَبَ becomes ضُرِبَ. In the present tense the first letter takes a damma and the letter before the last takes a fatha — يَضْرِبُ becomes يُضْرَبُ.
The older books name this role by describing it rather than titling it: اَلْمَفْعُولُ الَّذِي لَمْ يُسَمَّ فَاعِلُهُ, “the object whose doer has not been named”.
How to spot it
In the Qur'an
In the language — فِي اللُّغَة
The word نَائِب (na'ib) in everyday Arabic means a deputy — someone standing in for another.
نَائِبُ الرَّئِيسِ (na'ibu al-ra'isi) — “the vice-president”
As a grammatical term it means the word standing in for a doer that has not been named.
Related terms
Common questions
Is the na'ib al-fa'il just the object renamed?
It was the object before the verb was made passive. Once the doer is dropped it is promoted into his place, taking his rafa and the verb's agreement. Its meaning has not changed at all — only its grammatical position has.
Next in the guideاَلْمُبْتَدَأWhat is the subject (mubtada')? →Updated