Fearful image has captured mischievous spirit (6)
I believe the answer is:
phobic
'fearful' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'image has captured mischievous spirit' is the wordplay.
'image' becomes 'pic' (short for picture).
'has captured' means one lot of letters goes inside another.
'mischievous spirit' becomes 'hob' (hob can mean a fairy or spirit).
'pic' going around 'hob' is 'PHOBIC'.
Can you help me to learn more?
(Other definitions for phobic that I've seen before include "Suffering irrational fears" , "suffering morbid fear" , "With an irrational fear" .)