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.

---

loon ² American  

[loon] / lun /

noun

1. a crazy or simple-minded person.

---

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 )

---

loon ² British  

/ luːn /

noun

1. the US and Canadian name for diver

---

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

See Examples For:

loon

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

As for Foster, who first snagged my attention as the pathetic loon in “Alpha Dog,” he knows how to play a hiss-worthy heel.

From Los Angeles Times ● Sep. 11, 2025

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

Officials are caring for a common loon and a western grebe that were recovered with oil on their bodies.

From Los Angeles Times ● Mar. 11, 2024

And she would have been right—about him grinning like a loon.

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