Deserter's acronym (4)
I believe the answer is:
awol
'deserter's acronym' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for awol that I've seen before include "Not present when supposed to be" , "Absent without leave (abbr.)" , "Army offence of being missing from duty, briefly" , "Absent without leave (abbrev.)" , "unaccounted for" .)