Hit part of shirt (4)
I believe the answer is:
cuff
This clue is a double definition.
'hit' is the first definition.
(I've seen this before)
'part of shirt' is the second definition.
(part of a shirt sleeve)
(Other definitions for cuff that I've seen before include "by one hand" , "Smack; end of shirt sleeve" , "A slap" , "Part of garment covering wrist" , "Hit with the flat of the hand" .)