Debacle (6)
I believe the answer is:
fiasco
'debacle' is the definition.
(I know that debacle can be written as fiasco)
This is the entire clue.
(Other definitions for fiasco that I've seen before include "A hopeless mess or ludicrous failure" , "Humiliating disaster" , "Embarrassing failure" , "Ignominious failure" , "bomb" .)