flat-earther

noun

A person who believes or advocates the claim that the planet Earth is flat.

“When it comes to vaccine safety, they are diehard flat-earthers: the microchips and mercury are articles of faith.”

Similar
flat-earthistplatygaeanplatygaeanistflattardflerf
Opposite
globe-earthersphericistglobeheadgloberglobetard
Ask AI about this wordChatGPTClaudePerplexityGoogle AIGrok

Meanings

nounflat-earther (plural flat-earthers)

plural flat-earthers · alternative flat earther · alternative flatearther · alternative flat Earther · alternative flat-Earther

  1. A 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.

    Synonyms: flat-earthist, platygaean, platygaeanist, flattard, flerf · Antonyms: globe-earther, sphericist, globehead, glober, globetard

  2. broadlyderogatoryfigurativelyA 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.

    1 more example

    2008, Bob Sweere, "Voice of the Day: Global warming? Yes," News-Leader.com (Missouri), 16 Jun. (retrieved 1 July 2008), Global warming is settled, unless you are a flat earther or an energy company apologist.

Synonyms & antonyms

nounA person who believes or advocates the claim that the planet Earth is flat.

Similar
flat-earthistplatygaeanplatygaeanistflattardflerf
Opposite
globe-earthersphericistglobeheadgloberglobetard
Also see
flat-earthistflattardflerf

Origin

From flat-earth + -er.

Full word history & related roots →

Translations

Chinese Mandarin 地平論者 /地平论者
  • 地平論者 /地平论者 (dìpínglúnzhě)person who believes the Earth is flat
French terreplatiste, platiste
  • terreplatisteperson who believes the Earth is flat
  • platisteperson who believes the Earth is flat
German Flacherdler, Flacherdlerin
  • Flacherdlerperson who believes the Earth is flat
  • Flacherdlerinperson who believes the Earth is flat
  • Flachweltlerperson who believes the Earth is flat
  • Flachweltlerinperson who believes the Earth is flat
Greek επιπεδιστής, επιπεδίστρια
  • επιπεδιστής (epipedistís)person who believes the Earth is flat
  • επιπεδίστρια (epipedístria)person who believes the Earth is flat
Hungarian laposföld-hívő
  • laposföld-hívőperson who believes the Earth is flat
Italian terrapiattista
  • terrapiattistaperson who believes the Earth is flat
Polish płaskoziemiec, płaskoziemka
  • płaskoziemiecperson who believes the Earth is flat
  • płaskoziemkaperson who believes the Earth is flat
Portuguese terraplanista
  • terraplanistaperson who believes the Earth is flat
Russian плоскоземе́лец, плоскоземе́льщик
  • плоскоземе́лец (ploskozemélec)person who believes the Earth is flat
  • плоскоземе́льщик (ploskozemélʹščik)person who believes the Earth is flat
  • плоскоёб (ploskojób)person who believes the Earth is flat
Spanish terraplanista, tierraplanista
  • terraplanistaperson who believes the Earth is flat
  • tierraplanistaperson who believes the Earth is flat
Swedish plattjordare
  • plattjordareperson who believes the Earth is flat
Turkish düz dünyacı
  • düz dünyacıperson who believes the Earth is flat
Cite this entry
APA

flat-earther. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/flat-earther

MLA

“flat-earther.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/flat-earther. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “flat-earther,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/flat-earther.

Source: flat-earther on Wiktionary, CC BY-SA 4.0.