Illustration of cuckoo
- cuckoo 1
plural cuckoos
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
: to repeat monotonously as a cuckoo does its call
1
: of, relating to, or resembling the cuckoo
2
: deficient in sense or intelligence : silly
Did you know?
The cuckoo bird is so named for its one-note song, which in Middle English was represented as cuccu in imitation. Figurative use of cuckoo, which exists as an adjective meaning "crazy" or "weak in intellect or common sense," and as a noun for a person who can be described as such, may be an allusion to the bird's eponymous (and monotonous) call. But it may also be inspired by a peculiar habit exhibited by some species, in which a female will lay her eggs in the nest of another bird, to be hatched by that bird. In Old French, the name of the bird, cucu, also refers to a husband whose wife is unfaithful. That sense is believed to come from the female cuckoo bird's habit in some species of changing mates, or to the same egg-laying habit that influenced English figurative use. Cucu is also the source of English cuckold.
Synonyms
Noun
- berk [British]
- booby
- charlie [British]
- charley
- ding-a-ling
- ding-dong
- dingbat
- dipstick
- doofus [slang]
- featherhead
- fool
- git [British]
- goose
- half-wit
- jackass
- lunatic
- mooncalf
- nincompoop
- ninny
- ninnyhammer
- nit [chiefly British]
- nitwit
- nut
- nutcase
- simp
- simpleton
- turkey
- yo-yo
Adjective
- balmy
- barmy [chiefly British]
- bats
- batty
- bedlam
- bonkers
- brainsick
- bughouse [slang]
- certifiable
- crackbrained
- cracked
- crackers
- crackpot
- cranky [dialect]
- crazed
- crazy
- daffy
- daft
- demented
- deranged
- fruity [slang]
- gaga
- haywire
- insane
- kooky
- kookie
- loco [slang]
- loony
- looney
- loony tunes
- looney tunes
- lunatic
- mad
- maniacal
- maniac
- mental
- meshuga
- meshugge
- meshugah
- meshuggah
- moonstruck
- non compos mentis
- nuts
- nutty
- psycho
- psychotic
- scatty [chiefly British]
- screwy
- unbalanced
- unhinged
- unsound
- wacko
- whacko
- wacky
- whacky
- wud [chiefly Scottish]
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
Recent Examples on the Web
Cody Cottier, Discover Magazine, 28 Jan. 2025
For evolutionary biologists, the term cuckoldry originated to describe cuckoo birds who lay their eggs in other species’ nests, leaving their offspring to be unknowingly raised by foster parents.
—Brooke Scelza, Scientific American, 19 Sep. 2024
A.a. Dowd, Vulture, 20 May 2024
In the insect world, these include cuckoo bees, cuckoo bumblebees, and cuckoo wasps.
—Elizabeth Kolbert, The New Yorker, 27 Mar. 2023
Vulture, 3 Dec. 2022
For a host bird, raising a cuckoo baby along with its own young is expensive.
—Elizabeth Preston, Discover Magazine, 25 Apr. 2014
See all Example Sentences for cuckoo 
Examples are automatically compiled from online sources to
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Noun
Egg laying behavior of common cuckoos (Cuculus canorus): Data based on field video-recordings
The New York Academy of Sciences.
—Cody Cottier, Discover Magazine, 28 Jan. 2025
For evolutionary biologists, the term cuckoldry originated to describe cuckoo birds who lay their eggs in other species’ nests, leaving their offspring to be unknowingly raised by foster parents.
—Brooke Scelza, Scientific American, 19 Sep. 2024
Verb
Opinions are divided on whether Cuckoo is too absurd for its own good, but horror fans looking for a few scares in late August would be, well, cuckoo not to decide for themselves.
—A.a. Dowd, Vulture, 20 May 2024
In the insect world, these include cuckoo bees, cuckoo bumblebees, and cuckoo wasps.
—Elizabeth Kolbert, The New Yorker, 27 Mar. 2023
Adjective
Nick Offerman is also featured in the trailer as a cuckoo survivalist.
—Vulture, 3 Dec. 2022
For a host bird, raising a cuckoo baby along with its own young is expensive.
—Elizabeth Preston, Discover Magazine, 25 Apr. 2014
See all Example Sentences for cuckoo
Dictionary Entries Near cuckoo
Cite this Entry
“Cuckoo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cuckoo. Accessed 6 Feb. 2025.
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