Nearly a very small insect? (5)
I believe the answer is:
midge
'insect?' is the definition.
(midge is a kind of insect)
'nearly a very small' is the wordplay.
'nearly' means to remove the last letter.
'a very small' becomes 'midget' (I've seen this before).
'midget' with its final letter taken off is 'MIDGE'.
(Other definitions for midge that I've seen before include "Gnat" , "Small person" , "Small biting fly" , "Minute mosquito-like fly" , "Be an obstacle" .)