A stupid lout possesses little capacity for being mystical (6)
I believe the answer is:
occult
'being mystical' is the definition.
(I've seen this in another clue)
'a stupid lout possesses little capacity' is the wordplay.
'a stupid' is an anagram indicator (in a stupid order).
'possesses' is an insertion indicator.
'little capacity' becomes 'cc' (I've seen this in other clues. I am not sure about the 'little' bit.).
'lout' with letters rearranged gives 'oult'.
'oult' placed around 'cc' is 'OCCULT'.
'for' is the link.
Can you help me to learn more?
(Other definitions for occult that I've seen before include "Involving the supernatural or magical" , "Characteristic of supernatural phenomena" , "Hidden - paranormal" , "Esoteric, magical" , "Hidden; mystical" .)