Macho to eat head of insect? For the most part (6)
I believe the answer is:
mainly
'for the most part' is the definition.
(I've seen this before)
'macho to eat head of insect?' is the wordplay.
'macho' becomes 'manly' (I've seen this before).
'to eat' indicates putting letters inside.
'head of' suggests taking the first letters.
The initial letter of 'insect' is 'i'.
'manly' placed around 'i' is 'MAINLY'.
(Other definitions for mainly that I've seen before include "For the most part" , "Chiefly, principally" , "Generally or largely" , "Chiefly, largely" .)