opioid


opioid
/ˈoʊpiɔɪd/ (say 'ohpeeoyd)

noun
1. an endogenous peptide with pain-relieving properties similar to morphine.
2. opiate (def. 2).
adjective
3. of or relating to such a substance: opioid receptor; opioid analgesic.

Australian English dictionary. 2014.