Cleaner in Church Army (4)
I believe the answer is:
char
'cleaner' is the definition.
(charwoman is a type of cleaner)
'in church army' is the wordplay.
'in' indicates the answer is hidden within the clue.
'CHAR' can be found hidden inside 'church army'.
(Other definitions for char that I've seen before include "Daily cleaner; burn" , "Singe, scorch" , "Brown" , "House cleaner" , "Burn lightly" .)