1 of 2

noun (1)

plural loons
: lout, idler
chiefly Scotland : boy
: an eccentric person


2 of 2

noun (2)

: any of several large birds (genus Gavia of the family Gaviidae) of Holarctic regions that feed on fish by diving and have their legs placed far back under the body for optimal locomotion underwater

Illustration of loon

Illustration of loon

Did you know?

There are a number of theories about the origin of loon as it refers to a crazy person, its most common current meaning. One is that it comes from loony, meaning "crazy." But based on currently available evidence, loony is a late 19th-century alteration of lunatic that didn't come into use until decades after the meaning of loon in question. (It's still possible that loony influenced the development and spread of this meaning of loon.) Another guess is that this loon is from the avian loon, inspired either by the bird's maniacal cry or its displays to distract predators, such as skittering over water with its neck crooked. This is certainly possible, and is the origin story favored by some. But the story our dictionaries favor is a bit more quotidian: the current use of loon developed from earlier uses, primarily in Scottish and other northern dialects of British English, of loon to refer to a lout (an awkward, brutish person) or idler (someone who is idle, lazy, or inactive). While that loon, which is from Middle English loun, never spread to British English more broadly, immigrants from the regions where it was used had a significant influence on American English, and it's not far-fetched to posit that their loon developed into the distinctly American use of the word to refer to daffy people.

Examples of loon in a Sentence

Recent Examples on the Web
Share [Findings] In Maine, a loon stabbed a bald eagle through the heart. Rafil Kroll-Zaidi, Harper's Magazine, 2 Aug. 2023 Yellowstone National Park - Wyoming, Idaho, Montana Birds of Yellowstone National Park: Bald eagle, American white pelican, Canada geese, Common loon, Osprey, Sandhill crane, Trumpeter swan and American dipper. Camille Fine, USA TODAY, 29 July 2023 With more freezing temperatures possible, more of the birds could come tumbling down, loon experts say. Ben Kesling, wsj.com, 24 Apr. 2023 Three common terns and a common loon at the Hobbs Brook Reservoir, a common loon at Flint’s Pond in Lincoln, and an out of season dark-eyed junco in Arlington. Isabela Rocha, BostonGlobe.com, 8 July 2023 Abnormally cold weather in Wisconsin iced up the wings of migrating loons and caused dozens of them to fall from the sky over the past few days. Ben Kesling, wsj.com, 24 Apr. 2023 The 2021 Memorial Day weekend also brought other exciting loon news. Paul A. Smith, Milwaukee Journal Sentinel, 4 June 2021 Moose sightings are frequent, as are haunting loon calls. Melissa Findley, National Geographic, 20 Nov. 2020 According to the preamble, 30% of dead loons in a Wisconsin study were lead-poisoned. Paul A. Smith, Journal Sentinel, 19 Apr. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'loon.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Noun (1)

Middle English loun

Noun (2)

of Scandinavian origin; akin to Old Norse lōmr loon

First Known Use

Noun (1)

15th century, in the meaning defined at sense 1

Noun (2)

1634, in the meaning defined above

Time Traveler
The first known use of loon was in the 15th century


Dictionary Entries Near loon

Cite this Entry

“Loon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/loon. Accessed 27 Sep. 2023.

Kids Definition


: any of several large diving birds that eat fish, have a long pointed bill and webbed feet, and usually nest on the banks of lakes and ponds

More from Merriam-Webster on loon

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