USMC offense (4)
I believe the answer is:
awol
'usmc offense' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for awol that I've seen before include "Not present when supposed to be" , "Of soldier, illegally absent - initially" , "gone missing" , "Take unofficial leave (abbrev.)" , "On the lam" .)