Scourge (4)
(Other definitions for whip that I've seen before include "Beat (cream)" , "Strip of leather with handle, for beating" , "Cat-o'-nine-tails" , "Party official; punish" , "MP enforcing discipline" .)
'scourge' is the definition.
(synonyms)
This is all the clue.
(Other definitions for bane that I've seen before include "it causes misery" , "Something causing misery or distress" , "Cause of trouble or worry, like bean" , "scourge" , "Affliction, cause of distress" .)