Definition of: cuckoo

(kk′) noun
1. A bird belonging to a large family (Cuculidae), many species of which, as the common European cuckoo (Cuculus canorus), deposit their eggs in the nests of other birds to be hatched and cared for.
2. Any of various birds similar to the English cuckoo, as the Australasian small owl, or the American yellow-billed cuckoo (Coccyzus americanus) and the black-billed cuckoo (C. erythrophthalmus).
3. One who repeats the saying of another or follows slavishly, as in politics; a fool; ninny.
4. A cuckoo's cry.
5. One who commits adultery.
—v. ·ooed, ·oo·ing v.t. To repeat without cessation.
—v.i. To utter or imitate the cry of the cuckoo.
—adjective (also k′k) Slang Slightly deranged mentally; crazy; silly. [<OF cucu, coucou; imit.]