designating or of a group of natural or synthetic biochemicals, esp. endorphins, that relieve pain in the same way that opiates do
any such biochemical
Any of various compounds that bind to specific receptors in the central nervous system and have analgesic and narcotic effects, including naturally occurring substances such as morphine; synthetic and semisynthetic drugs such as methadone and oxycodone; and certain peptides produced by the body, such as endorphins. Also called opiate .
Origin of opioidopi(um) -oid
From opium +"Ž -oid.