Contradicter

Part of speech: noun

Definitions

1. A person who asserts the opposite of what someone else has said or refuses to accept their claim
2. Someone who speaks against another's assertion or directly denies the truth of their statement
3. An individual who takes issue with or disputes what another person maintains or declares

Etymology: "Contradicter" is simply the agent form of "contradict" with the suffix "-er," so it names a person who contradicts. The verb itself comes from Latin "contradicere," built from "contra" ("against") and "dicere" ("to say"), so the whole word means something like "to speak against." English took "contradict" from that Latin source, and adding "-er" to the English verb produces a person doing the speaking-against.

Synonyms: denier, objector, opponent, adversary

Antonyms: supporter, agreer