oxymorphone

[ ok-si-mawr-fohn ]
/ ˌɒk sɪˈmɔr foʊn /

noun Pharmacology.

a potent semisynthetic morphine-derived narcotic analgesic, C17H19NO4, used as a substitute for morphine.

Origin of oxymorphone

oxy-2 + morph(ine) + -one, components of its full chemical name