Found in academy thinking? Don't believe it! (4)
I believe the answer is:
myth
'don't believe it' is the definition.
(I've seen this in another clue)
'found in academy thinking?' is the wordplay.
'found in' says the answer is hidden in the clue.
'MYTH' can be found hidden inside 'academy thinking'.
(Other definitions for myth that I've seen before include "a false notion" , "There's no truth in it" , "Illusion" , "Fanciful story" , "A widely held but false belief" .)