Twist of fate (5)
I believe the answer is:
irony
'twist of fate' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for irony that I've seen before include "Form of satire, like Fe" , "situation showing incongruity" , "type of discussion, originally" , "Gentle sarcasm" , "Use of words to convey the opposite of what they normally mean" .)