Soldier and sailor back after leave (6,3)
I believe the answer is:
desert rat
'soldier' is the definition.
(I've seen this before)
'sailor back after leave' is the wordplay.
'sailor' becomes 'tar' (tar is a kind of sailor).
'back' says the letters should be written in reverse.
'after' is a charade indicator (letters next to each other).
'leave' becomes 'desert' (deserting is a kind of leaving**).
'tar' backwards is 'rat'.
'rat' after 'desert' is 'DESERT RAT'.
'and' acts as a link.
(Other definitions for desert rat that I've seen before include "WWII soldier" , "Old soldier" , "Tommy" , "Jerboa - WW2 British soldier in North Africa" , "Fighting man" .)