About half mine are unfinished (4)
I believe the answer is:
near
'about' is the definition.
('near' can be a synonym of 'about')
'half mine are unfinished' is the wordplay.
'half' suggests halving the letters.
'unfinished' means to remove the last letter.
'mine' cut in half is 'ne'.
'are' with its final letter taken away is 'ar'.
'ne'+'ar'='NEAR'
(Other definitions for near that I've seen before include "Close at hand" , "Miserly; approach" , "Verging on" , "Nigh" , "Close in time or place" .)