Desire wife to join worker (4)
I believe the answer is:
want
'desire' is the definition.
(synonyms)
'wife to join worker' is the wordplay.
'wife' becomes 'w' (abbreviation).
'to join' means one lot of letters go next to another.
'worker' becomes 'ant' (worker is a type of ant).
'w'+'ant'='WANT'
(Other definitions for want that I've seen before include "Need or desire" , "Wish" , "Lack, desire" , "Desire to possess" , "'Wilful waste makes woeful . . . .'" .)