HELLHOUND
Cerberus, hellhound
(noun) (Greek mythology) the three-headed dog guarding the entrance to Hades; son of Typhon
hellhound
(noun) a very evil man
Source: WordNet® 3.1
Etymology
Noun
hellhound (plural hellhounds)
(mythology) A demonic dog of hell, typically of unnatural size, strength or speed, with black fur, glowing eyes, and ghostly or phantom characteristics.
Source: Wiktionary
Hell"hound`, n. Etym: [AS. hellehund.]
Definition: A dog of hell; an agent of hell.
A hellhound, that doth hunt us all to death. Shak.
Source: Webster’s Unabridged Dictionary 1913 Edition