definition of drug: 1. Healing agent; any substance, except for nutrients, utilized in the prevention, prognosis, remedy, healing, or remedy of affliction. For sorts or classifications of medication, see the express title.
See additionally: agent.
2. To manage or take a drug, more often than not implying a very great quantity or a narcotic.
three. Well-known time period for any substance, stimulating or miserable, that may be habituating or addictive, distinctly a narcotic.