Humiliating failure (6)
I believe the answer is:
fiasco
'humiliating failure' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for fiasco that I've seen before include "Ignominious result" , "Total debacle" , "A ludicrous failure, a shambles" , "Sudden and complete collapse" , "Utter failure, debacle" .)