Words related to cuckoo

gowk (n.)
"cuckoo," early 14c., from Old Norse gaukr, from Proto-Germanic *gaukoz (source also of Old English geac "cuckoo," Old High German gouh). Meaning "fool" attested from c. 1600.
coo (v.)

1660s, "to utter a low, plaintive, murmuring sound," echoic of doves. Compare, in the same sense, Danish kurre, German girren; also Hindi kuku "the cooing of a dove," Persian huhu "a dove," and see cuckoo.

Meaning "to utter by cooing" is from 1798. Meaning "to converse affectionately, make love in murmuring endearments" is from 1816. Related: Cooing. The noun is recorded from 1729.

What are you doing now,
   Oh Thomas Moore?
What are you doing now,
   Oh Thomas Moore?
Sighing or suing now,
Rhyming or wooing now,
Billing or cooing now,
   Which, Thomas Moore? 
[Lord Byron, from "To Thomas Moore," 1816]
cuckold (n.)

derisive name for a man whose wife is false to him, "husband of an adulteress," early 13c., kukewald, cokewold, from Old French cucuault, from cocu (see cuckoo) + pejorative suffix -ault, of Germanic origin. So called from the female bird's alleged habit of changing mates, or her authentic habit of leaving eggs in another bird's nest.

In Modern French the identity is more obvious: Coucou for the bird and cocu for the betrayed husband. German Hahnrei (13c.), from Low German, is of obscure origin. The second element seems to be connected to words for "ardent," and suggests perhaps "sexually aggressive hen," with transferal to humans, but Kluge suggests rather a connection to words for "capon" and "castrated." The female equivalent, cuckquean, is attested by 1560s.

kooky (adj.)

1959, American English, originally teenager or beatnik slang, possibly a shortening of cuckoo.

Using the newest show-business jargon, Tammy [Grimes] admits, "I look kooky," meaning cuckoo. [Life magazine, Jan. 5, 1959]

Related: Kookily; kookiness.