cuckoo

UK: /ˈkʊkuː/ US: /ˈkuku, ˈkʊku/ ,(ko̅o̅′ko̅o̅, kŏŏk′o̅o̅)

Inflections of 'cuckoo' (v): (⇒ conjugate)

cuckoos

v 3rd person singular

cuckooing

v pres p

cuckooed

v past

cuckooed

v past p

WordReference Random House Learner's Dictionary of American English © 2025

cuck•oo /ˈkuku, ˈkʊku/   n., pl. -oos, v., -ooed, -oo•ing, adj. 
n. [countable]

1. Birds a slim, stout-billed, long-tailed bird.
2. Birds a common Eurasian cuckoo with a monotonous, repeated call.
3. the call of this cuckoo, or an imitation of it.
4. Slang Terms Informal. a crazy, silly, or foolish person.

adj. 

5. Slang Terms Informal. crazy;
   silly;
   foolish:
   a cuckoo idea.

WordReference Random House Unabridged Dictionary of American English © 2025

cuck•oo  (ko̅o̅′ko̅o̅, kŏŏk′o̅o̅), n., pl. -oos, v., -ooed, -oo•ing, adj. 
n. 

1. Birds a common European bird, Cuculus canorus, of the family Cuculidae, noted for its characteristic call and its brood parasitism.
2. any of several other birds of the family Cuculidae.
3. the call of the cuckoo, or an imitation of it.
4. Slang Terms a crazy, silly, or foolish person;
   simpleton.

v.i. 

5. to utter the call of the cuckoo or an imitation of it.

v.t. 

6. to repeat monotonously.

adj. 

7. Slang Terms crazy;
   silly;
   foolish.
8. of, pertaining to, or like a cuckoo.

• 1200–50; Middle English cuc(c)u, cuccuk(e) (imitative); compare Latin cucūlus, French coucou, German Kuckuk, Dutch koekoek, Modern Greek koûko

Collins Concise English Dictionary © HarperCollins Publishers::

cuckoo / ˈkʊkuː/ noun ( -oos)

1. 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
2. an irrational or foolish person

adjective

1. irrational or foolish

interjection

1. an imitation or representation of the call of a cuckoo

verb ( -oos, -ooing, -ooed)

1. (intransitive) to make the sound imitated by the word cuckoo

Etymology: 13th Century: from Old French cucu, of imitative origin; related to German kuckuck, Latin cucūlus, Greek kokkux