Jill's friend caught leaving appetisers for mischievous child (10)
I believe the answer is:
jackanapes
'mischievous child' is the definition.
(term for a mischievous person)
'jill's friend caught leaving appetisers' is the wordplay.
'jill's friend' becomes 'Jack' (as in the nursery rhyme Jack and Jill).
'caught' becomes 'c' (cricket abbreviation).
'leaving' is a deletion indicator.
'appetisers' becomes 'canapes' (I've seen this before).
'canapes' with 'c' taken away is 'anapes'.
'jack'+'anapes'='JACKANAPES'
'for' is the link.
(Other definitions for jackanapes that I've seen before include "Conceited, impertinent person" , "Someone unimportant but cheeky and presumptuous" , "Cheeky kid - Japan's cake (anag)" , "Cheeky sort" , "Cheeky chappie" .)