loon

¹ American  

[loon] / lun /

noun

1. any of several large, short-tailed, web-footed, fish-eating diving birds of the genus Gavia, of the Northern Hemisphere.

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loon ² American  

[loon] / lun /

noun

1. a crazy or simple-minded person.

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loon ¹ British  

/ luːn /

noun

1. informal a simple-minded or stupid person

2. dialect a lad

3. archaic a person of low rank or occupation (esp in the phrase lord and loon )

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loon ² British  

/ luːn /

noun

1. the US and Canadian name for diver

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Etymology

Origin of loon¹

First recorded in 1625–35; perhaps alteration of loom ³

Origin of loon²

1400–50; late Middle English lowen, perhaps < Old Norse lūinn worn, tired; later influenced by loon ¹ and loony ¹

Example Sentences

“Thanks for reading” was the suggested reply to someone who called me a hopeless loon and another guy who wondered why anybody would read my “dumb column.”

From Los Angeles Times • Mar. 14, 2026

In the season finale, Shane and Ilya steal away to Shane’s remote cottage on a lake north of Ottawa, where Ilya freaks out when he first hears the cry of a loon.

From The Wall Street Journal • Jan. 22, 2026

Since loons use the same foraging mode across their breeding range, the impact of water clarity on loon breeding success found in Wisconsin is likely to be echoed from Alaska to Iceland.

From Science Daily • Apr. 5, 2024

The Coast Guard said three live birds — a cormorant, a loon and a grebe — were found sullied with oil and were being treated.

From Seattle Times • Mar. 11, 2024

He figured he was smiling like a loon, but probably no one would fuss too much about that—probably.

From "Lizzie Bright and the Buckminster Boy" by Gary D. Schmidt