OPIOID
- a peptide that acts like opium [n OPIOIDS]
- pertaining to such a substance
- possessing some properties characteristic of opiate narcotics but not derived from opium
- any opiumlike substance
- any of a group of natural substances, as the endorphins, produced by the body in increased amounts in response to stress and pain
- any of several synthetic compounds, as methadone, having effects similar to natural opium alkaloids and their derivatives