a painful boil-like inflammation of the skin and deeper tissues with several openings for the discharge of pus
What is proposed [as an extension to the National Gallery] is like a monstrous carbuncle on the face of a much-loved and elegant friend — Charles, Prince of Wales
a red gemstone, usu a garnet, cut in a domed shape without facets
carbuncular /kahʹbungkyoolə/ adj
[Middle English via Old French from Latin carbunculus small coal, carbuncle, dimin. of carbon-, carbo charcoal, ember]