Chap comes out with those unfair comments (5,4)
I believe the answer is:
cheap shot
'unfair comments' is the definition.
(an unfair comment might be called a cheap shot)
'chap comes out with those' is the wordplay.
'comes out with' indicates anagramming the letters (I've seen 'coming out' mean this).
'chap' with its letters mixed up with 'those' can make 'CHEAP SHOT'.
(Other definitions for cheap shot that I've seen before include "Unkind act" , "Barbed comment exploiting known weakness of target" .)