Wiktionary
a. Relating to denial in a controversial debate. n. (context derogatory English) One who denies an assertion in a controversial debate.
Usage examples of "denialist".
These eight-" she pointed again "-are known Denialist strongholds, but we've been watching them since before the kidnapping, so it's not likely they could have slipped him in without us knowing it.
I tried to call him at the beginning of the third week but was put through to a trained denialist who flatly refused to admit that Tamworth or SO-5 even existed.
Spock, see if you can find any evidence of Professor Kostas, or any likely places where the Denialists could be holding him.
Only the Denialists, whom Haidar leads, are capable of sabotage and kidnapping for their cause.
Kirk had decided to make a simultane-ous raid on both suspected strongholds, so the Denialists could not move their captive once they realized their cover was blown.
All but one of them were decoys, no doubt, but the Denialists were rich.
That and the lack of a transporter grid overhead told Kirk that they had at least forced the Denialists into plan B.
If he were to succeed, the Denialists would have even less reason to hold him.