Green’s Dictionary of Slang

(drugs) marijuana.

1949		Monteleone Criminal Sl. (rev. edn) 154: megg marihuana.
1953		Anslinger & Tompkins Traffic In Narcotics 312: megg [...] Marihuana. Also a marihuana cigarette.
2001		ONDCP Street Terms 15: Meggie [...] Megg — Marijuana cigarette [...] Meg — Marijuana.
2002		A. Mariello ‘Dirty Dictionaries’ on Weekly Dig 🌐 He’s as thick as pig shit, but we like him anyway cos he always brings the megg and the morph, and he usually has surprises up his brown highway.