Green’s Dictionary of Slang

très adj.

very.

1920		F.S. Fitzgerald This Side of Paradise in Bodley Head Scott Fitzgerald III (1960) 203: ‘I’m tres old and tres bored, Tom,’ said Amory one day.
1920		Advocate (Burnie, Tas.) 5 June 7/2: Snorkey, you’re a snitty bonser! Tres beans! A snifter.
1972		B. Rodgers Queens’ Vernacular 200: très (tre or trez, fr Fr) very, so.
1990		(con. early 1950s) J. Ellroy L.A. Confidential 140: I’m très Hollywood.
1995		J. Stahl Permanent Midnight 185: Cynbill’s tres adorable male toddler, Zak.
2000		J.J. Connolly Layer Cake 27: The place is so fuckin exclusive [...] it’s tres exclusive, unlisted,a well-kept secret.