Rout (7)
'rout' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for trounce that I've seen before include "Defeat heavily (in contest)" , "Rout" , "Wallop" , "Defeat by large margin" , "Massacre" .)
'rout' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for debacle that I've seen before include "Rout; fiasco" , "Sudden and ignominious failure" , "Fiasco, a right mess" , "Sudden disastrous collapse or defeat" , "foul-up" .)