Deceptive or unreal (8)
I believe the answer is:
illusory
I believe this is a double definition.
'deceptive' is the first definition.
(I've seen this before)
'unreal' is the second definition.
(similar in meaning)
(Other definitions for illusory that I've seen before include "Unreal, fanciful" , "Deceptive" , "Fanciful, imaginary (8)" , "in the imagination" , "dreamed up" .)