deleterious

American  

[del-i-teer-ee-uhs] / ˌdɛl ɪˈtɪər i əs /

adjective

1. injurious to health.

   deleterious gases.

2. harmful; injurious.

   deleterious influences.

   Synonyms:

   noxious, destructive, hurtful, pernicious

   Antonyms:

   beneficial

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deleterious British  

/ ˌdɛlɪˈtɪərɪəs /

adjective

1. harmful; injurious; hurtful

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Other Word Forms

Derived Forms

• undeleteriously
  adverb
• undeleteriousness
  noun
• nondeleterious
  adjective
• deleteriously
  adverb
• undeleterious
  adjective
• nondeleteriously
  adverb
• deleteriousness
  noun
• nondeleteriousness
  noun

Etymology

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

Explanation

If something is deleterious, it does harm or makes things worse. Smoking has obvious deleterious effects on your health, not to mention your social life. My parents were worried that their divorce would have a deleterious effect on us kids, but in the end it was less harmful than watching them fight all the time. For most plants, a lack of sunlight has very deleterious consequences, but there are some plants that actually do very well in the dark. It's a wonder, given how well-established the science is, that we continue to do things that are deleterious to the fragile ecosystem. We must be willing to live with the deleterious effects.

Example Sentences

Reply to Dr. Mott's Article in Scientific American of November 16, entitled "Deleterious Use of Alum in Baking Powder." by w. p. clotworthy, baltimore, md.

From Scientific American, Vol. XXXIX.?No. 24. [New Series.], December 14, 1878 A Weekly Journal Of Practical Information, Art, Science, Mechanics, Chemistry, And Manufactures by Various

I ain't got the least idea what that means," said Toby, "but anyway it's the Churchwarden's voice, whether he calls himself Thomas the Inferior or Daniel the Deleterious.

From The Old Tobacco Shop A True Account of What Befell a Little Boy in Search of Adventure by Bowen, William

Deleterious, del-e-tē′ri-us, adj. tending to destroy life: hurtful or destructive: poisonous.—adv.

From Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) by Various

Deleterious Practice of allowing Children to eat at short Intervals.

From A Treatise on Domestic Economy For the Use of Young Ladies at Home and at School by Beecher, Catharine Esther

Deleterious indeed, Gerald! wherever did you pick up such a fine word?

From Tom Finch's Monkey and How he Dined with the Admiral by Anonymous