head drug
slang A substance that affects one's mental abilities or mood; a psychoactive, often hallucinogenic, drug. Come on, you went to Woodstock—you can't tell me you've never taken head drugs before. Nah, I don't want any magic mushrooms—I don't really like doing head drugs. A: "Why are they acting so weird?" B: "They're all tripping on some head drug, like acid or something."
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.