Ludicrous failure (6)
I believe the answer is:
fiasco
'ludicrous failure' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for fiasco that I've seen before include "A ludicrous or humiliating failure, complete mess" , "Ignominious result" , "An absolute mess, what a farce" , "Utter failure, debacle" , "Sudden total disaster" .)