Rent man beaten up in scrap (7)
I believe the answer is:
remnant
'scrap' is the definition.
(synonyms)
'rent man beaten up in' is the wordplay.
'beaten up' indicates anagramming the letters.
'in' indicates putting letters inside.
'man' anagrammed gives 'mna'.
'rent' enclosing 'mna' is 'REMNANT'.
(Other definitions for remnant that I've seen before include "Rent-man (anag.)" , "Residue" , "Little bit left" , "Piece or people left over" , "Scrap" .)