noc·​u·​ous ˈnä-kyə-wəs How to pronounce nocuous (audio)
nocuously adverb

Did you know?

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 the familiar innocent and the less familiar nocent, which 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.

Examples of nocuous in a Sentence

hand washing is one of the easiest ways to help prevent the spread of nocuous germs

Word History


Latin nocuus "harmful, noxious" (from nocēre "to injure, harm" + -uus, deverbal adjective suffix) + -ous — more at noxious

First Known Use

1627, in the meaning defined above

Time Traveler
The first known use of nocuous was in 1627


Dictionary Entries Near nocuous

Cite this Entry

“Nocuous.” Dictionary, Merriam-Webster, Accessed 1 Oct. 2023.

Medical Definition


noc·​u·​ous ˈnäk-yə-wəs How to pronounce nocuous (audio)
: likely to cause injury
a nocuous stimulus
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