Insect consumes fruit for nourishment (7)
I believe the answer is:
aliment
'nourishment' is the definition.
('aliment' can be a synonym of 'nourishment')
'insect consumes fruit' is the wordplay.
'insect' becomes 'ant' (ant is a kind of insect).
'consumes' means one lot of letters goes inside another.
'fruit' becomes 'lime' (lime is a kind of fruit).
'ant' going around 'lime' is 'ALIMENT'.
'for' acts as a link.
(Other definitions for aliment that I've seen before include "Old word for food" , "Sustenance" , "Nourishment" , "Something which nourishes - meal tin (anag)" .)