flightless

American  

[flahyt-lis] / ˈflaɪt lɪs /

adjective

1. incapable of flying.

   flightless birds such as the moa, rhea, and dodo.

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flightless British  

/ ˈflaɪtlɪs /

adjective

1. (of certain birds and insects) unable to fly See also ratite

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Etymology

Origin of flightless

First recorded in 1870–75; flight ¹ + -less

Explanation

Anything that's unable to propel itself through the air is flightless. You have at least one thing in common with a penguin: you're both flightless animals! The adjective flightless almost always describes birds that lost the ability to fly as they evolved, a group of about 60 species. When you imagine a flightless bird, you may picture the big, ungainly ones like emus and ostriches, but the tiny Inaccessible Island rail is also flightless. Wild turkeys can fly, but some turkeys, bred to be eaten on Thanksgiving, have bodies that are too wide and heavy for their wings to support them, and they've become flightless.

Example Sentences

Scientists believe Pennaraptora evolved feathers for flight, but environmental changes may have led some species to lose that ability over time, similar to flightless birds today such as ostriches and penguins.

From Science Daily • Mar. 18, 2026

For a people nicknamed after a flightless bird, taking off overseas has somewhat ironically become a rite of passage for many New Zealanders.

From BBC • Mar. 2, 2026

Before humans, flightless birds like the kākāpō and kiwi thrived.

From Slate • Aug. 8, 2025

Yet the malevolent flightless bird with a chip on his plumage isn’t the sole antagonist of “Vengeance Most Fowl.”

From Los Angeles Times • Dec. 19, 2024

It also formerly had a 400-pound ostrichlike flightless bird, plus some impressively big reptiles, including a one-ton lizard, a giant python, and land-dwelling crocodiles.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond