Sponger making soldiers mostly object (8)
I believe the answer is:
parasite
'sponger' is the definition.
(I know that sponger can be written as parasite)
'soldiers mostly object' is the wordplay.
'soldiers' becomes 'paras' (para is a kind of soldier).
'mostly' means to remove the last letter (most but not all of the word).
'object' becomes 'item' (both can mean a thing).
'item' with its last letter taken off is 'ite'.
'paras'+'ite'='PARASITE'
'making' is the link.
(Other definitions for parasite that I've seen before include "Organism that lives on another" , "unwanted guest" , "One living off another" , "Organism living off another" , "mistletoe sprig can be" .)