End a phone call (4,3)
'end a phone call' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ring off that I've seen before include "End a phone call" , "Slam down phone" , "Christian --, fashion designer" , "sign engagement's terminated?" , "Hang up" .)
(Other definitions for hang up that I've seen before include "Emotional inhibition? Replace telephone" , "Put the phone down" , "Modern term for emotional inhibition - get off the phone" , "Sever link" , "end conversation abruptly?" .)