Green’s Dictionary of Slang

1. (US) excellent, first-rate.

1920		H.C. Witwer No Base Like Home n.p.: Dedicated in gratitude to Charles Agnew MacLean, a beaucoup editor and a beaucoup guy.
1921		H.C. Witwer Leather Pushers 55: She’s a beaucoup looker.
1971		Army Reporter Feb. in Maledicta VI:1+2 252: ‘My, grandma-san, but you have beaucoup teeth,’ observes the Hood.
1986		L. Heinemann Paco’s Story (1987) 178: GI beaucoup number ten goddamned shit-eating fucking pig.
1995		J. Stahl Permanent Midnight 84: What she called Beaucoup Cajun Bush. Grass so strong, I actually noticed being high.
2008		R. Price Lush Life 199: ‘Nigger never get no dugout now.’ ‘I get bookoo dugout,’ Tristan said.
2012		C. Stella Rough Riders 16: I bet they both got themselves boo coo pussy.

2. many, plentiful.

1960		(con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 15: Boo-coo – plenty.
2021		J. Ellroy Widespread Panic 10: There’s boocoo pix of my bed.