Origin: 1605–15; < L noxius harmful, hurtful, injurious, equiv. to nox(a) harm, hurt, injury (akin to nocēre to do harm, inflict injury; see innocent) + -ius-ious
1612, from L. noxius "hurtful, injurious," from noxa "injury, hurt, damage entailing liability" (related to nocere "to hurt," and to nex "slaughter"), from PIE *nek-ro-, causative form of root *nek- "death" (cf. Skt. nasyati "disappears, perishes," Avestan nasyeiti, Gk. nekus "dead body, corpse," O.Ir. ec, Bret. ankou "death."
Main Entry: nox·ious Pronunciation: 'näk-sh&s Function: adjective : physically harmful or destructive to living beings <noxiouswastes that turn our streams into sewers>