narco UK /ˈnɑːkəʊ/US /ˈnɑɹkoʊ/ noun4 •(informal) Narcotics.Margo sighed her contentment. ‘Selling narco in Harlem is the life. There's nothing finer.’ — 1971 •A Latin American drug baron, usually from Colombia or Mexico.The conflict has become a test of endurance for both the government and the narcos. — 2010 •Acronym of narcotics control officer (“a police officer specializing in drug crimes”). •Someone suffering from narcolepsy.I too am a narco. Have been for about 10 years. — 1998 formsnarcos