Flower in black vase (4)
I believe the answer is:
burn
'flower' is the definition.
(thesaurus)
'black vase' is the wordplay.
'black' becomes 'b' (abbreviation as in pencil classifications).
'vase' becomes 'urn' (both can mean a container).
'b'+'urn'='BURN'
'in' acts as a link.
(Other definitions for burn that I've seen before include "Brand" , "Severely overcook" , "Set on fire" , "Scottish brook" , "Scorch; brook" .)