The Collaborative International Dictionary of English v.0.48:
Exterminator \Ex*ter"mi*na`tor\, n. [L.] One who, or that which, exterminates. --Buckle. [1913 Webster]WordNet (r) 3.0 (2006):
exterminator n 1: someone who exterminates (especially someone whose occupation is the extermination of troublesome rodents and insects) [syn: exterminator, terminator, eradicator]