cuckoo
Americannoun
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a common European bird, Cuculus canorus, of the family Cuculidae, noted for its characteristic call and its brood parasitism.
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any of several other birds of the family Cuculidae.
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the call of the cuckoo, or an imitation of it.
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Slang. a crazy, silly, or foolish person; simpleton.
verb (used without object)
verb (used with object)
adjective
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Slang. crazy; silly; foolish.
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of, relating to, or like a cuckoo.
noun
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any bird of the family Cuculidae, having pointed wings, a long tail, and zygodactyl feet: order Cuculiformes. Many species, including the European cuckoo ( Cuculus canorus ), lay their eggs in the nests of other birds and have a two-note call
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informal an insane or foolish person
adjective
interjection
verb
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(tr) to repeat over and over
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(intr) to make the sound imitated by the word cuckoo
Other Word Forms
Noun Inflected Forms
Etymology
Origin of cuckoo
1200–50; Middle English cuc ( c ) u, cuccuk ( e ) (imitative); compare Latin cucūlus, French coucou, German Kuckuk, Dutch koekoek, Modern Greek koûko
Explanation
A cuckoo is a type of long-tailed bird that's known for laying its eggs in the nests of other birds. In the summer, you're most likely to see cuckoos in various parts of Europe. The famous German cuckoo clock is named for the cuckoo bird, and the cuckoo sound the clock makes each hour imitates the call of the cuckoo. To make this call is also to cuckoo. Informally, you might refer to eccentric or crazy people or situations as cuckoo. Though this informal meaning is credited to American English, the word has been used to mean "stupid person" since at least the 1580s.
Vocabulary lists containing cuckoo
Amazing Animals, A-Z
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Soccer is just as cuckoo as any of our usual sports.
From The Wall Street Journal ● Jul. 20, 2026
And that has momentum traders going cuckoo for qubits.
From Barron's ● May 29, 2026
Like everyone in the movie, he sounds confident and totally cuckoo.
From Los Angeles Times ● Oct. 23, 2025
Nothing about “Another Simple Favor” or its equally cuckoo bananas predecessor, “A Simple Favor,” is subtle.
From Salon ● May 3, 2025
The modern cuckoo clock is a simplified version of these ‘automatic’ mechanisms.
From "The Invention of Science" by David Wootton
Among the more poignant moments, Charles laments the loss of wildlife at Highgrove, noting when he first moved in there nearly five decades ago he would hear cuckoos and see grasshoppers.
From Barron's ● Jan. 28, 2026
These efforts have helped protect a refuge for birds including willow flycatchers and yellow-billed cuckoos.
From Los Angeles Times ● May 26, 2024
There are two variants of female cuckoos: a gray morph that looks like a sparrowhawk, and a rufous morph.
From Science Daily ● Apr. 24, 2024
Pigeons, meanwhile, which were originally thought to be cousins with flamingos, belong to an entirely different branch and actually bear a much stronger genetic resemblance to cuckoos.
From Science Magazine ● Mar. 31, 2024
I snap the book shut and as if on cue, several cuckoos appear from intricately carved wooden clocks, announcing the hour half past.
From "The Bletchley Riddle" by Ruta Sepetys and Steve Sheinkin
She said she was cuckooed for months, and became "a prisoner in my own home".
From BBC ● Jun. 8, 2026
When the BBC visited the London properties with the Met police, officers said squalid conditions were the norm when it comes to cuckooed premises.
From BBC ● Jun. 8, 2026
During the week of action, 904 of these "cuckooed" homes were visited by law enforcement, and 1,138 vulnerable people were safeguarded, including 573 children.
From BBC ● May 26, 2021
When William Butler Yeats paid his first visit to that high priestess of occultism, Madame Blavatsky, the lady's pet cuckoo came out of a broken Swiss clock and cuckooed at him.
From Time Magazine Archive
It cuckooed eight times, then bounced back inside.
From The Cuckoo Clock by Barth, Ernie
Sgt Elise Wilson, who works closely with organisations like Positive Steps, said it was just one way cuckooing can be uncovered.
From BBC ● Aug. 7, 2024
She said cuckooing got its name from the bird, which is known for taking over the nests of other birds.
From BBC ● Aug. 7, 2024
It had 52 cuckooing referrals last year, compared to 29 in the previous 12 months.
From BBC ● Aug. 7, 2024
He added that cuckooing was a "horrendous practice" that the force was "determined to crack down on".
From BBC ● Jan. 28, 2022
The bands of searchers set off in eight different directions, shouting, hallooing, cuckooing, and making every kind of call likely to attract the child's attention.
From The School by the Sea by Brazil, Angela
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
