Discharge from army (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
demob
'discharge from army' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for demob that I've seen before include "Discharge from army" , "Retire from military service" , "Honourably discharge" , "put out of service" , "remove from service" .)