Word of the Day:

: harmful

Nocuous levels of toxic gases were detected in the coal mine.

"'We have had a lot of positive feedback from landholders who are thankful the council is doing something proactive to get rid of this nocuous weed,' [South Burnett councillor Kathy Duff] said. 'Lantana can seriously affect grazing country because it just takes over everything.'" - From an article in the South Burnett Times and Rural Weekly (Queensland), June 18, 2013

You are probably more familiar with the adjective "innocuous," meaning "harmless," than with its antonymous relative "nocuous." Both "nocuous" and "innocuous" have immediate Latin predecessors: "nocuus" and "innocuus." (The latter combines "nocuus" with the negative prefix "in-.") Both words can also be traced back to the Latin verb "nocēre," meaning "to harm." Other "nocēre" descendants in English include "innocent" and "nocent" (which also means "harmful"). "Nuisance" (which originally meant, and still can mean, "a harm or injury") is a more distant relative. "Nocuous" is one of the less common "nocēre" descendants, but it does turn up occasionally.