Green’s Dictionary of Slang

someone fortunate enough to have a trust fund to insulate them from work or ‘real life’; orig. used particularly of those who emulated the relaxed lifestyle of a Rastafarian although later uses imply no specific lifestyle.

1999		Indep. on Sun. Real Life 6 June 11: For trustafarians with little jobs in PR or interior design, a job is almost a lifestyle accessory.
2000		N. Barlay Crumple Zone 16: Slumming trustafarians in Gucci slingbacks and Versace wraps.
2005		P. Howard Curious Incident of the Dog in the Nightdress 271: The rest of you are all Trustafarians, aren’t you?
2015		J. Colapinto Undone 381: Isabel herself, her ankle encircled by a chain looped through the nipple ring of the dreadlocked, white, trustifundian piercing enthusiast.
2021		Betoota-isms 74: Trustafarian [...] 1. A young, wealthy white millennial who adopts a neo-hippie alternative lifestyle 2. A spoiled rich kid who embraces anti-Western counterculture, financially backed by their parents’ trust fund.