Villain:
1. A wicked or evil person; a deceitful and unreliable scoundrel; someone who is morally reprehensible.
2. A dramatic or fictional character who is typically at odds with the hero.

Thesaurus Synonyms:
* blackguard
* bounder
* cad
* dog
* hound
* heel
* knave
* persona non grata
* rapscallion
* rascal
* rogue
* scalawag
* scallywag
* scoundrel
* unwelcome person
* varlet