Definition of "goodnight"

I pray you ſpeake not: he growes worſe & worſe / Queſtion enrages him: at once, goodnight.

c. 1606 (date written), William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene iv], page 142, column 2

So goodnight to you—and goodnight, Councilor.

1914 September – 1915 May, Arthur Conan Doyle, “Lodge 341, Vermissa”, in The Valley of Fear: A Sherlock Holmes Novel, New York, N.Y.: George H[enry] Doran Company, published 27 February 1915, part II (The Scowrers), page 213

1932, Goodnight, Vienna

At last the pupils had all taken their hats and said their “Goodnights,” and Adam, knowing his old master's habits, rose and said, “Shall I put the candles out, Mr. Massey?”

1859, George Eliot [pseudonym; Mary Ann Evans], Adam Bede […], volumes (please specify |volume=I, II, or III), Edinburgh, London: William Blackwood and Sons

The afternoon passed into evening, and the sparrows began to twitter their goodnights in their lodgings on the roof and crevices of the chimney; […]

1873, E. H. D. Kay, Emma Simonet, Twilight Stories, page 153

George wakes, hearing the confused goodnights of the departing guests.

1919, Monica M. Gardner, The Anonymous Poet of Poland: Zygmunt Krasinski, page 114

Ray and Josh spoke their goodnights.

1999, Wanda Coleman, Mambo Hips and Make Believe: A Novel, page 100

With each one goodnighted / Including the pup, / Baby is sleeping / Bottom up.

1961 January 29, Annie Kendall, “Parade Rest”, in The Christian: International Weekly of the Christian Churches (Disciples of Christ), volume 99, number 5, St. Louis, Mo.: The Christian Board of Publication, page (155) 27

Then he goodnighted me, I changed into pyjamas and in a trice was sleeping the sleep of the unjust, which is quite as dreamless as the sleep of the just if the unjust sleeper has a litre of Red Hackle on his bedside table.

1979, Kyril Bonfiglioli, “After you with the pistol”, in The Mortdecai Trilogy, Black Spring Press, published 1991, pages 338–339

After eight hours of intense viewing, o-o-hing, and scribbling down plant names and ideas, a spent group of participants returned to our cars, goodnighted, and went our separate ways.

2010 fall, Jo Laskowski, “Hardy Fern Foundation Garden Tour, August 2010”, in Hardy Fern Foundation Quarterly, volume 20, number 4, page 85