Slight lifting for buttocks (4)
I believe the answer is:
buns
'buttocks' is the definition.
(synonyms)
'slight lifting' is the wordplay.
'slight' becomes 'snub' (snub is a kind of slight).
'lifting' says the letters should be written backwards.
'snub' reversed gives 'BUNS'.
'for' is the link.
(Other definitions for buns that I've seen before include "Cakes" , "Small rolls" , "Food items" .)