Leave work during strike (3,2)
I believe the answer is:
hop it
'leave' is the definition.
(I've seen this before)
'work during strike' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'during' indicates putting letters inside.
'strike' becomes 'hit' ('hit' can be a synonym of 'strike').
'op' put within 'hit' is 'HOP IT'.
(Other definitions for hop it that I've seen before include "Go away (colloq.)" , "Run along now!" , "split" , "Scram!" , "shove off" .)