Chap, married and bitter? (4)
I believe the answer is:
male
'chap' is the definition.
(chap can mean a man)
'married and bitter?' is the wordplay.
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'and' means one lot of letters go next to another.
'bitter?' becomes 'ale' (type of beer or bitter).
'm'+'ale'='MALE'
(Other definitions for male that I've seen before include "One cannot have babies" , "man?" , "Maldives capital; masculine" , "As are drakes, bulls etc." , "Lame sort of fellow" .)