Green’s Dictionary of Slang

1. (US gay) gay urban professionals, i.e. the gay equivalent of yuppie n.

1986		Sun. Times 12 Oct. 48: Subsequently the categorisation was refined to include the guppy (gay urban professional) and the bluppy (black urban professional).
1999		Gaymart.com Queer Sl. in the Gay 90s 🌐 Guppies – Gay urban professionals, or gay yuppies.
2000		Guardian G2 8 Mar. 3: Nimbys, dinkies, guppies, puppies.

2. (US) grown-up urban professional, i.e. one who has transcended the yuppie phase.

1989

H. Rawson Dict. of Invective (1991) 432: guppie, Grown-Up Urban Professional.