denier
n. countable C2 Proficiency de·nier
n. a person who refuses to believe that something is true, especially when there is clear evidence. You often hear this word when people talk about climate change or history.
n. a person who refuses to accept the truth or reality of something, typically in the face of overwhelming evidence. Often used in the context of historical revisionism or scientific consensus.
He is a climate change denier who ignores the data.
The website was shut down because it provided a platform for Holocaust deniers to spread their false claims.
From Old French denier, from Latin dēnārius. Doublet of denar, denarius, dinar, diner, dinero, and dinheiro.
From deny + -er.