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' is an anagram indicator.
'in' means one lot of letters goes inside another.
'man' anagrammed gives 'mna'.
'rent' placed around '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" .)