Rent man injured in scrap (7)
I believe the answer is:
remnant
'scrap' is the definition.
(synonyms)
'rent man injured in' is the wordplay.
'injured' indicates an anagram.
'in' indicates putting letters inside.
'man' with letters rearranged gives 'mna'.
'rent' placed around 'mna' is 'REMNANT'.
(Other definitions for remnant that I've seen before include "Scrap" , "Piece or people left over" , "Piece of leftover fabric" , "rest" , "offcut" .)