Strike part of sleeve (4)
I believe the answer is:
cuff
This clue is a double definition.
'strike' is the first definition.
(I've seen this before)
'part of sleeve' is the second definition.
('cuff' is part of 'sleeve')
(Other definitions for cuff that I've seen before include "Smack; Moonstone sergeant" , "Wrist end of sleeve" , "There may be a link with this" , "[SLEUTH]" , "Blow - on the wrist?" .)