cuck·​oo | \ ˈkü-(ˌ)kü How to pronounce cuckoo (audio) , ˈku̇- How to pronounce cuckoo (audio) \
plural cuckoos

Definition of cuckoo

 (Entry 1 of 3)

1 : a largely grayish-brown European bird (Cuculus canorus) that is a parasite given to laying its eggs in the nests of other birds which hatch them and rear the offspring broadly : any of a large family (Cuculidae of the order Cuculiformes) to which this bird belongs
2 : the call of the cuckoo
3 : a silly or slightly crackbrained person


cuckooed; cuckooing; cuckoos

Definition of cuckoo (Entry 2 of 3)

transitive verb

: to repeat monotonously as a cuckoo does its call



Definition of cuckoo (Entry 3 of 3)

1 : of, relating to, or resembling the cuckoo
2 : deficient in sense or intelligence : silly

Illustration of cuckoo

Illustration of cuckoo


cuckoo 1

In the meaning defined above

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Synonyms & Antonyms for cuckoo

Synonyms: Noun

Synonyms: Adjective

Antonyms: Adjective

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Examples of cuckoo in a Sentence

Noun one cuckoo at the campground tried to boil soup in a plastic cup didn't want to be among those cuckoos who race around the mall the day before Christmas Adjective a cuckoo woman who wandered around town carefully gathering up useless trash offered a completely cuckoo suggestion for using the defunct strip mall
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Recent Examples on the Web: Noun During the 20-minute periods outside the incubator the 15 warbler eggs lost 4.42°C on average, whereas the 15 cuckoo eggs lost an average of 4.15°C. The Economist, "Convergent evolutionThicker eggshells help cuckoos hatch earlier than their nestmates," 18 Jan. 2018 It's known commonly as a cuckoo bee, but its scientific name is a mouthful: Epeoloides pilosulus (EE'-pee-oh-loy-deez pil-OH'-syou-lus)., "A rare cuckoo bee — thought to have gone extinct — spotted in Wisconsin’s Northwoods," 23 Aug. 2019 The Epeoloides pilosulus, a type of cuckoo bee, was once widespread across eastern and central North America but was thought to have gone extinct. Sophie Carson, Milwaukee Journal Sentinel, "Hive five! Scientists make un-bee-lievable discovery of rare cuckoo bee in Chequamegon-Nicolet National Forest," 22 Aug. 2019 Their relationship is believable — cuckoo, but believable. Soren Andersen, The Seattle Times, "‘The Spy Who Dumped Me’: Kate McKinnon makes familiar action comedy something special," 30 July 2018 In it, Vernon tries hard to entertain a new blue avian friend, unaware that Bird is not sentient but rather a wooden cuckoo fallen from a clock. New York Times, "Brief Tales for New Readers and Little Listeners From Philip Stead and More," 29 June 2018 Workers in Silicon Valley and the San Francisco-Oakland area, driven out of the cuckoo housing markets in those communities, have snapped up cheaper properties in Stockton, accepting the bargain of killer commutes. Steve Lopez,, "Stockton's young mayor has bold turnaround plan: Basic income and stipends for potential shooters," 27 May 2018 Here, for example, is the call of the mangrove cuckoo, a small bird found mainly in coastal South Florida forests. Tarpley Hitt, miamiherald, "A lesson from mating birds: The song gets sweeter over time, a Miami scientist finds | Miami Herald," 29 Mar. 2018 Their destination was Zhalong National Nature Reserve, where reed warblers are parasitised by common cuckoos. The Economist, "Thicker eggshells help cuckoos hatch earlier than their nestmates," 18 Jan. 2018 Recent Examples on the Web: Adjective The movie is a colorful, cuckoo-crazy, sometimes funny, often bewildering experience. Katie Walsh, Detroit Free Press, "‘Angry Birds 2’ is chaotic, occasionally thoughtful," 12 Aug. 2019 In this very cuckoo moment, Double Shot turned sincere, even sad. Darren Franich,, "In praise of the goofy, shocking, endearing Double Shot at Love finale," 28 June 2019 These cuckoo conspiracy theories are symptomatic of a shift in global values from the optimism of the 1990s, when America’s liberal democracy was universally admired, to the current era of fear and anger, when democracy is in retreat. Trudy Rubin,, "Roseanne's other twisted tweet of the week. (The one you didn't already read about) | Trudy Rubin," 1 June 2018 Celebrities and designers are cuckoo for them: Adele performs with one in her pocket, Kim Kardashian West designed her fragrance after their unique forms, and Mary-Kate and Ashley Olsen offered them to guests at The Row’s most recent fashion show. Rachel Waldman, Vogue, "This Model-Turned-Baker Makes Otherworldly Candy Crystals," 6 Apr. 2018 Alva’s just one of many San Antonians who’s downright cuckoo for Funko Pops. René A. Guzman, San Antonio Express-News, "San Antonio one of many cities madly collecting Funko Pop! figures," 6 Apr. 2018 In cases like these, in which subjects are claiming harm from a cuckoo experiment, the system is set up to punish the institution rather than give redress to the subject. Marisa Taylor, Washington Post, "Unregulated Herpes Experiments Expose ‘Black Hole’ Of Accountability," 21 Dec. 2017 Host birds like reed warblers are wise to the possibility of cuckoo parasitism. Cathleen O'grady, Ars Technica, "Cuckoo calls sound like hawks to distract the birds they’re preying on," 8 Sep. 2017 No manual transmission is available, since many of the car’s active-safety systems don’t play nice with the stick, and Audi tossed the last gen’s lightning-quick dual-clutch auto because Americans are cuckoo for pudding-smooth stoplight launches. Car and Driver, "New Cars for 2018: Audi," 10 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cuckoo.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of cuckoo


13th century, in the meaning defined at sense 1


1648, in the meaning defined above


1627, in the meaning defined at sense 1

History and Etymology for cuckoo


Middle English cuccu, of imitative origin

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Time Traveler for cuckoo

Time Traveler

The first known use of cuckoo was in the 13th century

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Statistics for cuckoo

Last Updated

7 Oct 2019

Cite this Entry

“Cuckoo.” The Dictionary, Merriam-Webster Inc., Accessed 5 December 2019.

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More Definitions for cuckoo


How to pronounce cuckoo (audio) How to pronounce cuckoo (audio)

English Language Learners Definition of cuckoo

 (Entry 1 of 2)

: a type of bird that lays its eggs in the nests of other birds and that has a call that sounds like its name



English Language Learners Definition of cuckoo (Entry 2 of 2)

informal + old-fashioned
: silly or crazy
: very enthusiastic


cuck·​oo | \ ˈkü-kü How to pronounce cuckoo (audio) , ˈku̇- \
plural cuckoos

Kids Definition of cuckoo

1 : a grayish brown European bird that lays eggs in the nests of other birds which hatch and raise them
2 : the call of the cuckoo

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More from Merriam-Webster on cuckoo

Thesaurus: All synonyms and antonyms for cuckoo

Rhyming Dictionary: Words that rhyme with cuckoo

Spanish Central: Translation of cuckoo

Nglish: Translation of cuckoo for Spanish Speakers Encyclopedia article about cuckoo

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