Feeble chap's wife a trouble-maker (4)
I believe the answer is:
wimp
'feeble chap's' is the definition.
'wife a trouble-maker' is the wordplay.
'wife' becomes 'w' (abbreviation).
'a trouble-maker' becomes 'imp'.
'w'+'imp'='WIMP'
(Other definitions for wimp that I've seen before include "Spineless type" , "Informally, an ineffectual man" , "Softie" , "Spineless man" , "Someone ineffectual" .)