It's in the levy! (5)
I believe the answer is:
tithe
'levy' is the definition.
(tithe is a kind of levy)
'it's in the' is the wordplay.
'it's' becomes 'it' (I've seen this in other clues).
'in' is an insertion indicator.
'it' inserted within 'the' is 'TITHE'.
(Other definitions for tithe that I've seen before include "Tenth part (as tribute)" , "Levy by church, e.g." , "Offering" , "Tax paid to church" , "One-tenth of income paid to church" .)