/nem"euh sis/ , n. , pl. nemeses /-seez'/ .
1. something that a person cannot conquer, achieve, etc.: The performance test proved to be my nemesis.
2. an opponent or rival whom a person cannot best or overcome.
3. ( cap. ) Class. Myth. the goddess of divine retribution.
4. an agent or act of retribution or punishment.
[ némesis lit., a dealing out, verbid of némein to dispense (justice); see -SIS ]
Syn. 1. Waterloo. 4. downfall, undoing, ruin, Waterloo.