carbuncle

noun

1. 1.A deep-red or fiery colored garnet or other dark red precious stone, especially when cut cabochon.
2. 2.A charge or bearing supposed to represent the precious stone, with eight sceptres or staves radiating from a common centre; an escarbuncle.
3. 3.An abscess larger than a boil, usually with one or more openings draining pus onto the skin. It is usually caused by bacterial infection.
4. 4.An unpopular or ugly building; an eyesore.