Green’s Dictionary of Slang

(drugs) marijuana.

1997		Da Bomb Summer Supplement 5: Endo (n.) Marijuana.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 65/2: endo n. marijuana.
2007		UGK ‘Underground Kingz’ 🎵 While I’m tapping ass, leaning back smoking some endo.