Lop off (4)
'lop off' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sever that I've seen before include "Cut or break off, perhaps a relationship" , "Cut completely" , "split" , "Disconnect" , "Cut apart, maybe a relationship" .)
(Other definitions for chop that I've seen before include "Hew" , "Karate punch" , "Cut - a piece of meat" , "Cut into small pieces" , "Dissect" .)