IPA: /tɔːrˈmɛntər/
KK: /tɔrˈmɛntər/
A person or thing that causes great suffering or distress to others.
The bully was a tormentor to many students at the school.
Tormentor → It is formed from "tormentum" (meaning a tool for twisting or torture) and the suffix "-or" (meaning one who). The word "tormentor" refers to one who inflicts pain or suffering, often through torture.
Think of someone who uses a 'tool for twisting' ('tormentum') to cause pain — that's why a tormentor is someone who inflicts suffering.