Troops in a body, almost (5)
I believe the answer is:
corps
'troops' is the definition.
'a body almost' is the wordplay.
'a body' becomes 'corpse' (corpse is a kind of body).
'almost' means to remove the last letter (most of the word but not all of it).
'corpse' with its final letter removed is 'CORPS'.
'in' acts as a link.
(Other definitions for corps that I've seen before include "Large army group" , "ballet group" , "Branch of an army" , "Body of men" , "Large body of troops" .)