Also found in: Idioms, Wikipedia.


One who stubbornly adheres to outmoded or discredited ideas.

[From the long-discredited belief that the earth is flat.]

flat′-earth′ adj.


informal a person who does not accept or is out of touch with the realities of modern life
References in periodicals archive ?
Even the most stubborn flat-earther now has to concede that timing different stages of a race tells us how its development has favoured some and worked against others.
It worries me that instead of having a sensible conversation on just how much man is responsible for changing the climate, anyone who doesn't toe the man-the-planet-destroyer line is now barracked as a fool and a flat-Earther.
He is reliably neither left nor right, Muslim or Christian, patriot, populist, Martian or Flat-Earther.
Lutton's resume as a highly educated flat-earther would be of little consequence here except that he also occupies this seat at one of the most significant anti-immigrant think tanks.
If my criticism of globalization makes me a flat-earther, so be it.
Other Flat-Earther attendees echoed sentiments about loneliness.