Green’s Dictionary of Slang

1. (orig. US) anything sticky or viscid, e.g. blood, semen, glue.

1900		E.H. Babbitt ‘College Words and Phrases’ in DN II:i 38: goo, n. 1. Any liquid. 2. Anything sticky. 3. Dirty moisture.
1908		Burley & Scott [perf. Florrie Forde] Girls, study your cookery-books 🎵 You’ll find he won't get blue / If you properly cook his goo.
1911		E. Ferber Dawn O’Hara (1925) 33: D’you mean to tell me that you woke me [...] to make me drink that goo? What is it, anyway, I’ll bet it’s another egg-nog.
1923		H.C. Witwer Fighting Blood 14: ‘Well, I ordered a sundae,’ butts in Judy, dipping her spoon in this rich goo.
1934		‘J.M. Hall’ Anecdota Americana II 97: G stands for Gism, / The grandest of goos.
1942		in Randolph & Legman Ozark Folksongs and Folklore (1992) II 600: [of venereal pus] I rolled my dick out on the table, / And the gooey goo comes oozin’ out.
1951		Kerouac On the Road (The Orig. Scroll) (2007) 330: Spittle on his chin, piss on his pants, [...] goo in his nose.
1953		J. Thompson Savage Night (1991) 108: Little gobs of that goo kept [...] trickling down onto me.
1962		in E. Cray Erotic Muse (1992) 280: Let me pinch your boobies till they’re black and blue. / Let me stroke your vulva till it’s filled with goo.
1972		D. Morrell First Blood 209: A drop of rotten goo pelted his nose.
1977		E. Bunker Animal Factory 20: The coffee had loosened the night’s phlegm. He hacked and spat the goo on the asphalt.
1985		S. Berkoff West in Decadence and Other Plays (1985) 117: Travelling salesmen swilling down some unidentified goo.
1999		Indep. Mag. 3 July 22: Physical movement was like wading through a vat of goo.
2000		Guardian Travel 15 Jan. 4: They’ll splatter you with a tankard of goo scooped from tin baths.
2003		C. Stella Charlie Opera 48: I hate it when your goo [i.e. semen] starts running out while I’m working.

2. (also goo-ga) patter, e.g. of a carnival tout.

1929

T. Thursday ‘And Howe’ in Everybody’s Feb. 🌐 ‘Here’s the goo,’ I says. ‘Take it home and study it for a hour or so.’ [Ibid.] I stepped to the front and unwound a fair line of assorted goo-ga.

3. sickly sentimentality, esp. in speech or writing.

1922		Joyce Ulysses 297: Bloom putting in his old goo [...] talking about the Gaelic league and the antitreating league and drink, the curse of Ireland.
1936		Times (Munster, IN) 26 Aug. 12/2: It is too much like Babbitt’s paradise of goo and gush.
1951		T. Thursday ‘Score None for the Chair’ in Smashing Detective Sept. 🌐 A very touching tale [...] He could write some of that detective goo I hear on the radio.
1954		Wodehouse Jeeves and the Feudal Spirit 37: Some fellows, no doubt, would take advantage of this outstanding goo.
1990		S. Morgan Homeboy 319: Mushed into the subterraneous goo of lamister whore dreams.
1999		Indep. on Sun. Culture 7 Nov. 2: Churning out glossy goo like this.