› a natural or artificially made substance that is used as a medicine: an anti-cancer drug The state is grappling for ways to curb rising drug costs in its $1 billion Medicaid drug budget.
› a natural or artificially made substance, especially one that is illegal, which is taken for pleasure, to improve performance in an activity, or because someone is addicted (= cannot stop taking it): a banned/illegal drugtake/abuse drugs He admitted abusing drugs and alcohol his entire adult life before ending up in jail. → See also prescription drug