injurious to health: deleterious gases.
harmful; injurious: deleterious influences.

Origin of deleterious

1635–45; < Greek dēlētḗrios destructive, adj. derivative of dēlētḗr destroyer, equivalent to dēlē- variant stem of dēleîsthai to hurt, injure + -tēr agent suffix + -ios adj. suffix; see -ious
Related formsdel·e·te·ri·ous·ly, adverbdel·e·te·ri·ous·ness, nounnon·del·e·te·ri·ous, adjectivenon·del·e·te·ri·ous·ly, adverbnon·del·e·te·ri·ous·ness, nounun·del·e·te·ri·ous, adjectiveun·del·e·te·ri·ous·ly, adverbun·del·e·te·ri·ous·ness, noun

Synonyms for deleterious

Antonyms for deleterious Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for undeleterious

Historical Examples of undeleterious

  • It contained inhabitants of as undeleterious and self-satisfied a class of peasantry as ever clustered around a Maypole.

British Dictionary definitions for undeleterious



harmful; injurious; hurtful
Derived Formsdeleteriously, adverbdeleteriousness, noun

Word Origin for deleterious

C17: from New Latin dēlētērius, from Greek dēlētērios injurious, destructive, from dēleisthai to hurt
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 undeleterious



1640s, from Medieval Latin deleterius, from Greek deleterios "noxious," from deleter "destroyer," from deleisthai "to hurt, injure." Related: Deleteriously; deleteriousness.

Online Etymology Dictionary, © 2010 Douglas Harper

undeleterious in Medicine




Having a harmful effect; injurious.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.