Defeat overwhelmingly (4)
I believe the answer is:
bury
'defeat overwhelmingly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bury that I've seen before include "League Two team" , "Put under ground" , "Forget - cover with soil" , "Lancs. town" , "Completely envelop" .)