He has skill on the organ (5)
I believe the answer is:
heart
'the organ' is the definition.
(the heart is an organ of the body)
'he has skill' is the wordplay.
'has' is a charade indicator (letters next to each other).
'skill' becomes 'art' (both can mean a talent).
'he'+'art'='HEART'
'on' acts as a link.
(Other definitions for heart that I've seen before include "Crux" , "Centre; core" , "Kernel" , "Vital part" , "Body organ" .)