Smart black vase (4)
I believe the answer is:
burn
'smart' is the definition.
(burning is a kind of smarting)
'black vase' is the wordplay.
'black' becomes 'b' (abbreviation as in pencil classifications).
'vase' becomes 'urn' (both can mean a container).
'b'+'urn'='BURN'
(Other definitions for burn that I've seen before include "Cremate" , "be consumed" , "Go up in flames; stream" , "Feel hot, small stream" , "Scottish brook" .)