Trounce

18 clues
Beat
Flog
Rout
Paste
Thrash
Clobber
Shellac
Beat badly
Beat soundly
Beat handily
Beat by a lot
Utterly defeat
Defeat soundly
Beat decisively
Defeat decisively
Give a shellacking
Give a whupping to
Wipe the floor with
Similar answers:
Abedandtroy
Accostcontrols
Actlikeatrouper
Adaptivecontrol
Adisserctroilus
Admissioncontrol
Agathatroy
Agentroomheader
Aheapofhotrodders
Albatross
Albatrosses
Allofourpatrons
Allotrope
Allyourtroubles
Altro
Altrock
Ambidetrous
Ambidextrous
Ambidextrously
Americantrotter