IPA: //fləˈdʒɛl.ənt//
KK: /flædʒəˌlænt/
A person who inflicts pain on themselves or others, often through whipping, usually for religious reasons or as a form of sexual gratification.
The flagellant believed that self-punishment would bring them closer to spiritual purity.
Flagellant → It is formed from "flagellare" (meaning to whip) and the suffix "-ant" (indicating a person who performs an action). The word refers to a person who engages in the act of whipping themselves, often for religious penance.
Think of someone 'whipping' ('flagellare') themselves as a form of penance — that's why a flagellant is a person who performs this act.