Man in church with a piano (4)
I believe the answer is:
chap
'man' is the definition.
(I've seen this in other clues)
'church with a piano' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'with' means one lot of letters go next to another.
'piano' becomes 'p' (musical abbreviation).
'ch'+'a'+'p'='CHAP'
'in' is the link.
(Other definitions for chap that I've seen before include "Raw, cracked patch on skin" , "we prefer not to have on hand" , "Fish" , "Fellow; sore skin area" , "cove" .)