Weigh down (6)
'weigh down' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for oppress that I've seen before include "Treat tyrannically" , "Crush, subjugate" , "Trample down" , "Abuse" , "Weigh down with cares, be cruel" .)
'weigh down' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for burden that I've seen before include "Onerous weight" , "Load or responsibility carried" , "Onerous or difficult load" , "A heavy load or difficulty" , "Oppressive duty" .)