Opening puzzle suspiciously... young compiler has evil mind (6)
I believe the answer is:
psyche
'mind' is the definition.
(I know that mind can be written as psyche)
'opening puzzle suspiciously young compiler has evil' is the wordplay.
'opening' says to take the initial letters.
The initial letters of 'puzzle suspiciously young compiler has evil' is 'PSYCHE'.
(Other definitions for psyche that I've seen before include "Human mind or soul" , "Inner self" , "Core of one's personality" , "Human mind or spirit" , "Soul - girl from Greek mythology" .)