Green’s Dictionary of Slang

veg v.

also veg out
[abbr. SE vegetate]

to do nothing, to lapse into a totally apathetic and passive state.

[US]Baker et al. CUSS 218: Veg Waste time, not study.
[Can]Totally True Diaries of an Eighties Roller Queen [Internet] 17 Mar. Today I went to Tracey’s to pick up my guitar and stuff [...] I then went home and vegged out.
[Aus]Tracks (Aus.) Dec. 3: Those blokes who sat there and veged must have been on smack or something [Moore 1993].
[UK]K. Lette Llama Parlour 91: While you’ve been sittin’ here veggin’ out all night, I’ve had twelve sensational orgasms.
[US]Eble Sl. and Sociability 70: In the late 1980s and early 1990s, the nationally recognized couch potato for ‘someone who lies around doing nothing more energetic than eating and watching television’ was still in use, along with [...] the verbs potato and veg.
[UK]Observer Mag. 9 Jan. 36: Experts identify ‘vegging out’ with the TV as a major cause of lost time, fatigue and dissatisfaction.
(con. 1980s) i80s.com [Internet] veg Term used to describe chilling out or taking it easy.
[Aus]L. Redhead Rubdown [ebook] I was exhausted [...] and felt like vegging out in front of the TV.
[US]J. Ridley What Fire Cannot Burn 242: Eddi had come to know Vin liked to sit and talk. Sit and watch TV. Sit and veg.