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speed freak

or speed·freak

noun Slang.
  1. an addict or habitual user of amphetamines, methamphetamines, or similar stimulating drugs.

Origin of speed freak

First recorded in 1965–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for speedfreak

speedfreak

noun
  1. slang an amphetamine addict
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012