Stop to put in end part of sleeve (3,3)
I believe the answer is:
cut off
'stop' is the definition.
(cutting off is a kind of stopping)
'to put in end part of sleeve' is the wordplay.
'put in' indicates putting letters inside.
'end part of sleeve' becomes 'cuff' (I've seen this before).
'to' inserted within 'cuff' is 'CUT-OFF'.
(Other definitions for cut off that I've seen before include "Keep from contact, or disinherit" , "(Fuel) flow interrupter" , "Designated limit" , "Severed- without a penny?" , "Disconnect" .)