Fleeting craze (3)
I believe the answer is:
fad
'fleeting craze' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fad that I've seen before include "Passing vogue or fashion" , "Passing craze or peculiar notion" , "A craze, usually passing" , "Affectation" , "A passing fashion or craze" .)