Genius dashing off some art (7)
I believe the answer is:
maestro
'genius' is the definition.
(I've seen this before)
'off some art' is the wordplay.
'off' is an anagram indicator.
'some'+'art'='someart'
'someart' is an anagram of 'MAESTRO'.
'dashing' is the link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for maestro that I've seen before include "Great figure" , "Master of an art, or a great conductor of music" , "Means of payment" , "A master of any art, like music" , "Distinguished artist" .)