flat-earther
A person who believes or advocates the claim that the planet Earth is flatA person who believes or advocates the claim that the planet Earth is flat.
Meaning
2 sensesA person who believes or advocates the claim that the planet Earth is flat.
His commitment to remaining a flat-earther seems to be strengthened by counterarguments rather than weakened by them.
Flacherdler, Flacherdlerin, Flachweltler
плоскоземе́лецploskozemélec, плоскоземе́льщикploskozemélʹščik, плоскоёбploskojób
(broadly, derogatory, figuratively)A person who believes or advocates an outlandish, discredited theory; a person who refuses to acknowledge the truth despite overwhelming evidence.
When it comes to vaccine safety, they are diehard flat-earthers: the microchips and mercury are articles of faith.