flat-earther

noun

flat-earth·​er ˌflat-ˈər-thər 

variants or less commonly flat-earthist

ˌflat-ˈər-thist 

: a person who believes that the planet Earth is flat

Examples of flat-earther in a Sentence

Recent Examples on the Web

Unfortunately, the resources don’t exist to take every flat-earther to the International Space Station to change their mind. — Torie Bosch, STAT, 2 May 2026

To suggest this vaccine doesn’t work better than natural immunity is flat-earther stuff. — Jody Mamone, Hartford Courant, 2 Jan. 2026

Debbie’s anger at flat-earthers turned out to run deeper, in fact, than her anger at metabolism-tracking devices. — Camille Bordas, New Yorker, 7 Dec. 2025

In general, most flat-earthers believe Earth is a flat, hockey-puck-like object covered by a dome, sometimes called a firmament, with walls of ice around the edges of the dome. — Terry Collins, USA Today, 8 Apr. 2024

Google denied that there was any evidence that LaMDA was sentient, and experts agreed, in a tone that made those who would say otherwise seem like flat-earthers. — Josh Morgenthau, Washington Post, 5 Aug. 2023

Modern flat-earthers came out of the mid to late nineteenth century with the explosion of the Industrial Revolution. — Justin E. H. Smith, Harper's Magazine, 21 Aug. 2022

Word History

First Known Use

1926, in the meaning defined above