Remains bottom (4)
I believe the answer is:
rump
This clue is a double definition.
'remains' is the first definition.
(thesaurus)
'bottom' is the second definition.
(rump can informally mean someone's bottom)
(Other definitions for rump that I've seen before include "Fleshy hindquarters" , "Tail end" , "Mammal's hind part" , "Depleted legislators" , "Cut of meat form animal's hindquarters" .)