WordNet (r) 3.0 (2006):

awol
    adj 1: absent without permission; "truant schoolboys"; "the
           soldier was AWOL for almost a week" [syn: truant,
           awol]
    n 1: one who is away or absent without leave

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "AWOL":
   French leave, abscondence, absence, absence without leave,
   absent without leave, absentation, absenteeism, absenting,
   absquatulation, bolt, cut, day off, decampment, default, departure,
   desertion, disappearance, disappearing act, elopement, escape,
   excused absence, exit, fleeing, flight, fugitation, furlough,
   hasty retreat, hegira, holiday, hooky, leave, leave of absence,
   leaving, nonappearance, nonattendance, quick exit, running away,
   sabbatical leave, scramming, sick leave, skedaddle, skedaddling,
   truancy, truant, truantism, unexcused absence, vacation



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

AWOL
       Absent WithOut Leave (telecommunication, Usenet, IRC)