Yank - painful parting (6)
I believe the answer is:
wrench
I believe this is a double definition.
'yank' is the first definition.
(I've seen this before)
'painful parting' is the second definition.
(I've seen this before)
(Other definitions for wrench that I've seen before include "Jerky pulling movement" , "Pull awkwardly (away)" , "Kind of spanner or severe twist" , "Sort of spanner - twist it" , "Tear away" .)