|Kanji in this term|
- an exterminator
Has Buddhist overtones, from the Buddhist sense of 退治 meaning “driving out evil”. By extension, this term is often used in fiction to refer to an “exterminator” of spiritual or supernatural problems. The literal underlying meaning of the kanji compound is 退 (“drive back, force out”) + 治 (“suppress, rule, control, make peaceful”).
A more general term for an “exterminator” would be 根絶者 (konzetsusha) (as of a disease or a problem), while a more formal or bussiness-like term for an exterminator of pests would be a 駆除業者 (kujo gyōsha). More specifically, an exterminator of insects would be a 害虫駆除業者 (gaichū kujo gyōsha), and an exterminator of other animals would be a 害獣駆除業者 (gaijū kujo gyōsha).