The term “narcotic” is based on the Greek word “narcosis”, the term used by Hippocrates for the process of benumbing, benumbed or sedated state. A “narcotic” substance refers to agents that benumb or deaden, and by metaphorical extension those that cause loss of feelings, or sedation.
“Narcotics” are usually understood as substances that produce a general sense of well-being, sometimes known as euphoria, deep relaxation, and a reduction of tension and anxiety.
Yet this term is often used inaccurately: in the U.S.A’ s legal context for instance, “narcotic” refers to opium, opium derivatives, and their semi-synthetic or fully synthetic substitutes "as well as cocaine and coca leaves," which although classified as "narcotics" in the U.S. Controlled Substances Act (C.S.A.), are not narcotics in their effects or chemistry, but stimulants.
The term narcotic is also sometimes applied to any illegal substance, even to cannabis or psychedelics. Because this term is often used so broadly, inaccurately or pejoratively outside of medical contexts, most specialists prefer to speak of “narcotic effects”, and substitute other more precise terms such as “opioid” or “opiates” for this class of substances and modes of actions.