Suit in church covering big belly (7)
I believe the answer is:
costume
'suit' is the definition.
(thesaurus)
'church covering big belly' is the wordplay.
'church' becomes 'CE' (abbreviation for Church of England).
'covering' indicates putting letters inside.
'big' becomes 'os'.
'belly' becomes 'tum' (I've seen this before).
'os'+'tum'='ostum'
'ce' enclosing 'ostum' is 'COSTUME'.
'in' acts as a link.
(Other definitions for costume that I've seen before include "(Historic etc) dress" , "Attire worn in a play or at a fancy dress ball" , "Theatrical clothes" , "ensemble" , "Clothing" .)