IPA: /lɪˈbɛl.ər/
KK: /lɪˈbɛlɚ/
A person who makes false statements about someone in order to damage their reputation, usually in written form.
The journalist was sued for being a libeller after publishing untrue claims about the politician.
**Libeller** → It is formed from "libelle" (from Old French, meaning a small book or pamphlet) and the suffix "-er" (meaning a person who). A libeller is a person who writes or publishes a defamatory statement, often in a small written form.
Think of a 'small book' ('libelle') where someone writes something negative about another person — that's why a libeller is someone who writes defamatory statements.