Green’s Dictionary of Slang

a greeting or celebratory gesture that takes the form of raising the arm and ritualistically slapping palms with someone.

1988		W.D. Myers Me, Mop, and the Moondance Kid 57: After the game everybody was slapping hands and giving each other high-fives and everything.
1989		P. Benchley Lush 116: She smiled and stamped her foot and gave herself a highfive.
1992		K. Lette Llama Parlour 99: He delivered his jock-speak like punches [...] punctuated with finger-snaps and high-fives.
2000		T. Udo Vatican Bloodbath 7: The disciples started giving each other high fives and whooping and hugging each other.
2009		Observer Mag. 4 Jan. 20: How d’you do? [...] Everyone gave you a high five?
2009		P. Temple Truth 42: He offered a high-five to Villani. Villani didn’t take it, he was not a high-five man.
2009		L. McIlvanney All the Colours 302: [L]anguid, consolatory high-fives.
2011		Observer 20 Feb. 33/5: R. Kelly is giving Winston from the band high fives.
2016		Guardian Guide 21 May 11/3: The security guy [...] gives him a high five.
2017		Young M.A. ‘Walk’ 🎵 Give my blood niggas high-fives, hi five.
2021		P Howard Braywatch 49: Richie is getting the high-five the next time I see him.