Involved in subterfuge, king deposed by mischievous Greek (9)
I believe the answer is:
intricate
'involved' is the definition.
(synonyms)
'in subterfuge king deposed by mischievous greek' is the wordplay.
'subterfuge' becomes 'trick' (subterfuge is trickery or deceit).
'king' becomes 'K' (abbreviation for king in chess).
'deposed' suggests deleting specific letters.
'by mischievous greek' becomes 'ate' (I am not sure about this - if you are sure you should believe this answer much more).
'trick' with 'k' removed is 'tric'.
'in'+'tric'+'ate'='INTRICATE'
Can you help me to learn more?
(Other definitions for intricate that I've seen before include "puzzlingly obscure" , "puzzling" , "Convoluted" , "Entangled" , "ornate" .)