Black art, maybe (3)
I believe the answer is:
tar
'black' is the definition.
(I've seen this in other clues)
'art maybe' is the wordplay.
'maybe' is an anagram indicator.
'art' anagrammed gives 'TAR'.
(Other definitions for tar that I've seen before include "Dark viscous stuff" , "Product of coal" , "Road surfacing or old sailor" , "Sticky black stuff" , "Seaman; pitch" .)