A person who waits around to steal your lover from you at the first opportunity.

The cuckoo, who usually plays the role of being a "friend", is likely to be a friend of your significant other's best friend's partner. They use the convenience of "let's go out as s foursome" as part of their swooping technique.

Just as the real cuckoo waits for an opportunity to get into another bird's nest, then throws out their eggs and takes it over as their own. The cuckoo swoops in, and starts dating your partner.
"I knew that Dave bloke was sniffing around and wanted to be more than her friend. Fucking cuckoo stole my nest!"
by Abcd432 October 17, 2015
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This is another informal word for a woman's vagina
She barely even knows how to use her cuckoo, yet she's still trying to give it away
by Brigette Martin Mendoça July 21, 2017
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guy1: yeah that's right. I'm nuts. But damn it's fun, you coming along for the ride?
guy2: you cuckoo !
by lina khlewi May 25, 2012
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Dishca
Dishca adds bleach to her water, she is cuckoo!
by Anonymous June 24, 2003
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A midwit, or someone or middling intellect, who gets caught up in some form of mass hysteria. Strong supporters of a nanny state mentality to the point of insanity, and excellent examples of the Dunning Kruger effect in action. Named after the John Wyndham novel "the Midwich Cuckoos".
"Look at these midwit cuckoos, they want all dogs put down because some child got bitten by one recently."

"This guy says all humans must be exterminated to save the planet. What a midwit cuckoo."
by RayBidd February 10, 2022
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The action of announcing the time and number of hours left in a work day at annoyingly short intervals.
"Seven thirty, eight and half more hours until quitting time."
"Stop Cuckoo clocking! Nobody cares how much longer we have to work today."
by Zarl June 24, 2009
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