Definitions
1.nounAn archenemy"Batman is in constant conflict with his nemesis, The Joker."
2.noun(chiefly non-North American usage) A person or character who specifically brings about the downfall of another person or character.
3.nounThe principle of retributive justice.
4.noun(usually in the singular) A punishment or defeat that is deserved and cannot be avoided.
5.nounThe polar opposite of a character.
6.nounA righteous infliction of retribution manifested by an appropriate agent.