A regular or habitual user of drugs for non-medicinal purposes, especially a person who takes illegal drugs for their narcotic, stimulant, or mood-altering effects.
Origin
Early 20th century.
Definition of drug abuser in US English:
drug abuser
noun
A regular or habitual user of drugs for non-medicinal purposes, especially a person who takes illegal drugs for their narcotic, stimulant, or mood-altering effects.