Heraldic black (5)
I believe the answer is:
sable
'heraldic black' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sable that I've seen before include "Type of fur" , "North Asian marten" , "Bales of valuable Russian fur" , "Dark brown - black" , "(Fur from) small carnivore" .)