False appearance (8)
I believe the answer is:
illusion
'false appearance' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for illusion that I've seen before include "A false belief about linus oil" , "Something a person wrongly believes to exist" , "False belief or image, like mirage" , "can you believe it?" , "Chimera" .)