head drug(redirected from a head drug)
slang A substance that affects one's mental abilities and/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.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. a drug that affects the mind rather than the body; a psychoactive drug. It’s these head drugs that get the kids into so much trouble.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.