I'm bowled over by craze which deceives viewers (6)
I believe the answer is:
mirage
'which deceives viewers' is the definition.
(a mirage is an optical illusion)
'i'm bowled over by craze' is the wordplay.
'bowled over' says the letters should be written backwards.
'by' is a charade indicator (letters next to each other).
'craze' becomes 'rage' (synonyms).
'im' back-to-front is 'mi'.
'mi'+'rage'='MIRAGE'
(Other definitions for mirage that I've seen before include "unreal" , "vision" , "French flier" , "French fighter aircraft" , "Illusion caused by atmospheric refraction" .)