harmful or injurious to health or physical well-being: noxious fumes.
morally harmful; corrupting; pernicious: a noxious plan to spread dissension.

Origin of noxious

1605–15; < Latin noxius harmful, hurtful, injurious, equivalent to nox(a) harm, hurt, injury (akin to nocēre to do harm, inflict injury; see innocent) + -ius -ious
Related formsnox·ious·ly, adverbnox·ious·ness, noun

Synonyms for noxious

Antonyms for noxious

1, 2. harmless. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for noxious

Contemporary Examples of noxious

Historical Examples of noxious

  • No, he does not find it; brambles are there and noxious weeds galore.

    The Book of Khalid

    Ameen Rihani

  • The excreta of that army of sick poisoned the air with their noxious emanations.

    The Downfall

    Emile Zola

  • At Verdun, along the entire frontier, there were nests of these noxious vermin.

    A Nest of Spies

    Pierre Souvestre

  • With blood and iron we will ourselves stamp out this noxious breed.

    The Burning Spear

    John Galsworthy

  • Now it happens that he is noxious to us—let the reasons be what they may.

    St. Martin's Summer

    Rafael Sabatini

British Dictionary definitions for noxious



poisonous or harmful
harmful to the mind or morals; corrupting
Derived Formsnoxiously, adverbnoxiousness, noun

Word Origin for noxious

C17: from Latin noxius harmful, from noxa injury
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for noxious

c.1500, from Latin 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" (see necro-).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for noxious




Harmful to living things; injurious to health.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.