Policeman has right to yield (4)
I believe the answer is:
crop
'to yield' is the definition.
(crop is a kind of yield)
'policeman has right' is the wordplay.
'policeman' becomes 'cop' (slang term).
'has' indicates putting letters inside.
'right' becomes 'r' (common abbreviation).
'cop' placed around 'r' is 'CROP'.
(Other definitions for crop that I've seen before include "Expanded part of bird's throat" , "Cut short the season''s yield?" , "Cut short the harvest" , "(Yield from) cultivated plant" , "Season's produce" .)