Green’s Dictionary of Slang

(drugs) marijuana.

1936		C.R. Cooper Here’s to Crime n.p.: Commonly it now being called ‘fu’, ‘mezz’, ‘mu’, ‘moocah’, ‘muggles’, ‘weed’ and ‘reefers’.
1940		‘Jargon of Marihuana Addicts’ in AS XV:3 Oct. 336/2: The drug, itself, is known as [...] moocah, mu [...].
1953		Anslinger & Tompkins Traffic In Narcotics 312: moocah [...] Marihuana.
1969		R.R. Lingeman Drugs from A to Z (1970) 180: moocah [...] marijuana.
1971		E.E. Landy Underground Dict. (1972) 134: moocah [...] Marijuana.
2001		ONDCP Street Terms 15: Mooca/moocah — Marijuana.