Definition of cuckoo in US English:



  • 1A medium-sized long-tailed bird, typically with a gray or brown back and barred or pale underparts. Many cuckoos lay their eggs in the nests of small songbirds.

    Family Cuculidae (the cuckoo family): numerous genera and species, especially the (Eurasian) cuckoo (Cuculus canorus), the male of which has a well-known two-note call. The cuckoo family also includes the coucals, roadrunners, and anis

    • ‘The wet season (mid-June to early October) is hot and humid and the best time for flowering plants, amphibians, reptiles and intra-African migrant birds such as cuckoos.’
    • ‘To investigate further, the biologists took to subalpine forests in the foothills of Mount Fuji, where the cuckoos lay their eggs in the nests of red-flanked bush robins.’
    • ‘Two cuckoo and two magpie nestlings were removed from different nests a day before being tested together in a same artificial nest.’
    • ‘It is an important wintering ground for European migratory birds such as the white stork, the lesser kestrel, the Eurasian golden oriole, the Eurasian cuckoo and other wading birds.’
    • ‘Two species in whose nests these cuckoos' eggs have been found, and which are known to eject cowbird eggs, did not significantly eject more nonmimetic than mimetic cuckoo eggs.’
    • ‘Birds that bring up young cuckoos are unable to distinguish between parasitic nestlings and their own.’
    • ‘A ground-dwelling cuckoo, Delalande's coucal lived in Madagascar, off the east coast of Africa, along with an array of strange animals found there.’
    • ‘Sitting like cuckoos in the nests of other birds, these castles were positioned pragmatically to reuse extant defensive features while allowing ready access to wider hinterlands and keeping civilian populations in check.’
    • ‘Parasitic cuckoos, cowbirds and weavers lay many more eggs per season than their non-parasitic relatives.’
    • ‘The most distinct feature of the cuckoo is the long tail.’
    • ‘This ability might represent an escalation in an arms race between superb fairy-wrens and cuckoos, the researchers suggest in the March 13 Nature.’
    • ‘So while superb fairy-wrens would be better off abandoning cuckoos at the egg stage, because this has become so difficult it pays to abandon the cuckoo chick instead.’
    • ‘The pheasant cuckoo is a bird that took Stauffer and me a succession of trips to locate.’
    • ‘Every year one of the topics commonly discussed here is who heard the first cuckoo of the season.’
    • ‘They feed their chicks with food that is digestible for the cuckoo chick, and they have a nest size and egg size that make it possible for the young cuckoo to eject the nest contents.’
    • ‘Her data supported a tree topology in which Coccyzus is nested within a single clade comprising all of the parasitic cuckoos.’
    • ‘Unlike common cuckoos, young indigobirds are reared along with their hosts and they mimic the mouth markings of host nestlings.’
    • ‘As hosts evolve defenses against parasitism by cuckoos, cuckoos evolve ever better means of tricking hosts into rearing their young, which, in turn, promotes the evolution of improved host defenses.’
    • ‘The cuckoo, a bird we are both enchanted with, is one we are quite sure we've never seen.’
    • ‘As cities grow in all directions, horizontally and vertically, there is hardly any space left for trees to grow, for the cuckoos to build their nest or parrots to rest on branches and prattle away.’
  • 2informal A mad person.

    • ‘It sure didn't take new Portland coach Mo Cheeks long to pick up the company line on resident cuckoo Rasheed Wallace.’
    • ‘Savage seems to be living in cloud cuckoo land in a couple of key respects.’
    • ‘What is this, the first stop off the bus from cuckoo land?’
    • ‘She was probably listening to her iPod and drifted off to cuckoo land again.’
    • ‘And he went further, saying that anybody who believed the association could afford it was ‘living in cuckoo land’.’
    • ‘If you honestly believe that had he been the prime minister, Britain would not have aided our closest ally the US in Iraq then I'm sorry, you're living in cuckoo land.’
    • ‘Which cloud cuckoo lands does Count Roy Davies live in?’
    • ‘Perhaps this explains that cuckoo '96 NBA offseason, which saw a handful of players land outrageous contracts.’
    • ‘Without mincing words, I am afraid he is living in cloud cuckoo land.’
    lunatic, maniac, psychotic, psychopath, schizophrenic
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  • Mad; crazy.

    ‘people think you're cuckoo’
    • ‘For months afterwards I had panic attacks - I didn't want to say anything to anybody because I thought I was going cuckoo.’
    • ‘India's policy-makers must emerge from their cuckoo world of neo-liberal economics and corporate-driven politics.’
    • ‘When we feel cuckoo, it's easy to feel victimized by our own cuckoo feelings.’
    • ‘Any bad weather which came at the end of April or early May was dismissed as a mere cuckoo storm that would only last a day or two.’
    • ‘I turned out I wasn't the only one whose parents had gone cuckoo on them.’
    • ‘Sure she's cuckoo, but I've seen newborn puppies who were more harmful than her.’
    • ‘A chartered surveyor from Strathaven, in Lanarkshire, who owns a terraced property two doors along, said: ‘Property prices in this place are just cuckoo.’’
    • ‘The whole thing was cuckoo enough that it might be true.’
    • ‘But these people are cuckoo about Ronald Reagan.’
    • ‘We have a researcher who was a former chip designer who came to the conclusion that this trend is cuckoo.’
    • ‘The inventive production is a work of art in its own right, every bit as cuckoo as the play.’
    • ‘But now I see why someone could go cuckoo over a koala.’
    • ‘Thus, simple math reveals that Lewis is certifiably cuckoo.’
    • ‘Her anti-feminist manifesto is the final crazy coating on this already cuckoo confection.’
    • ‘But just look at him… how could any red-blooded woman not be totally cuckoo?’
    • ‘People are going cuckoo over the intriguing chapter titles, which include: ‘What Do Schoolteachers and Sumo Wrestlers Have in Common?’’
    • ‘But it would be a mistake to dismiss them as just cuckoo.’
    • ‘I remember him saying ‘This guy's got this cuckoo magazine in New York City, you ought to check it out.’’
    • ‘He'd think that I'm cuckoo and refuse to associate me anymore.’
    • ‘When I visited him he was like a zombie; the drugs, the antidepressants they gave him had left him cuckoo.’
    severely mentally ill, mentally ill, insane, mad, certifiable, deranged, demented, of unsound mind, out of one's mind, not in one's right mind, not together, crazed, maniac, maniacal, lunatic, unbalanced, unhinged, unstable, disturbed, distracted, stark mad, manic, frenzied, raving, distraught, frantic, hysterical, delirious, mad as a hatter, mad as a march hare
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  • cuckoo in the nest

    • An unwelcome intruder in a place or situation.

      • ‘The collapse of Psion's joint venture with Motorola is major bad news for the British company, but isn't likely to cause significant ripples for the cuckoo in the Psion nest, Symbian.’
      • ‘It is about time the BBC got a grip and culled these cuckoos in its nest.’
      • ‘But what once looked like a fledgling of which they might be proud has turned into a cuckoo in the nest.’
      • ‘Where once Nato was about European protection, is it not now becoming the cuckoo in the nest of European ambitions?’
      • ‘At first Deakin seemed a cuckoo in the Berry nest - what would later be called a class traitor.’


Middle English: from Old French cucu, imitative of its call.