Man perhaps introduced to crazy fool (7)
I believe the answer is:
mislead
'fool' is the definition.
(I know that fool can be written as mislead)
'man perhaps introduced to crazy' is the wordplay.
'man perhaps' becomes 'isle' (Isle of Man is an example).
'introduced to' is an insertion indicator.
'crazy' becomes 'mad' (synonyms).
'isle' going inside 'mad' is 'MISLEAD'.
(Other definitions for mislead that I've seen before include "Fool" , "Give a wrong impression to (someone)" , "Cause someone to have a false belief" , "Take someone in the wrong direction" , "Deceive" .)