Cuckoo (noun)

1. A bird with a distinctive call, typically with a barred plumage and a long tail.
2. An eccentric or crazy person.
3. A thing or person that is not what it seems or is out of place.

Origin:

From old english cuccu, imitating the bird's call.

Examples:

1. The cuckoo bird is known for its distinctive call.
2. He was called a cuckoo for his strange behavior.
3. The clock was a cuckoo clock, with a bird that came out to call the hour.
4. The cuckoo bird is a brood parasite, laying its eggs in the nests of other birds.
5. He felt like a cuckoo in the nest, not belonging in the group.