Soldier with place for sponger (8)
I believe the answer is:
parasite
'for sponger' is the definition.
(I've seen this before)
'soldier with place' is the wordplay.
'soldier' becomes 'para' (paratrooper).
'with' means one lot of letters go next to another.
'place' becomes 'site' (site is a kind of place).
'para'+'site'='PARASITE'
(Other definitions for parasite that I've seen before include "Creature that lives off others" , "Possibly tick" , "unwanted guest" , "it sucks blood" , "It lives off its host" .)