What is mellow yellow

What Is Mellow Yellow? 1. slang A nickname for the psychedelic drug lysergic acid diethylamide (LSD). What drug is mellow yellow? 1. slang A nickname for the psychedelic drug lysergic acid diethylamide (LSD). What is the meaning of Mellow Yellow? Being mellow, laid-back, chilled out. ‘They call me Mellow Yellow, I’m the guy who can…