Absentee (6)
I believe the answer is:
truant
'absentee' is the definition.
(truant is a kind of absentee)
This is the entire clue.
(Other definitions for truant that I've seen before include "Child bunking off school" , "One is absent from school without permission" , "Wandering" , "One playing hooky" , "Inexcusably absent" .)