A bit much -- a pregnant bloke! (4)
I believe the answer is:
chap
'bloke' is the definition.
(thesaurus)
'a bit much a pregnant' is the wordplay.
'a bit' indicates the answer is hidden within the clue (the answer is formed by a bit of the clue).
'CHAP' is hidden within 'much a pregnant'.
(Other definitions for chap that I've seen before include "we prefer not to have on hand" , "Become sore; fellow" , "Fish" , "Man, boy, fellow" , "(Of skin) become sore" .)