caustic
Americanadjective
noun
-
a caustic substance.
-
Optics.
adjective
-
capable of burning or corroding by chemical action
caustic soda
-
sarcastic; cutting
a caustic reply
-
of, relating to, or denoting light that is reflected or refracted by a curved surface
noun
-
Also called: caustic surface. a surface that envelops the light rays reflected or refracted by a curved surface
-
Also called: caustic curve. a curve formed by the intersection of a caustic surface with a plane
-
chem a caustic substance, esp an alkali
Other Word Forms
- caustical adjective
- caustically adverb
- causticity noun
- causticly adverb
- causticness noun
- noncaustic adjective
- noncaustically adverb
- overcaustic adjective
- overcaustically adverb
- overcausticity noun
- uncaustic adjective
- uncaustically adverb
Etymology
Origin of caustic
1350–1400; Middle English < Latin causticus < Greek kaustikós burning, caustic, equivalent to kaust ( ós ) burnt (verbal adjective of kaíein to burn) + -ikos -ic
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Okrent portrays Sondheim as witty and endearing, but also poorly groomed, remote, caustic, quick to anger — and, mostly, quick to forgive.
From Los Angeles Times • Mar. 17, 2026
At this point, you just don’t like each other, which makes communication feel even more caustic.
From MarketWatch • Feb. 27, 2026
Around him orbits a constellation of classmates - caustic, thoughtful, restless - who debate Swiss-French architect Le Corbusier, Karl Marx and the price of cigarettes with equal seriousness.
From BBC • Feb. 13, 2026
I have enjoyed the caustic verve of this Claude.ai promotional campaign, which seems to be heading off the inevitable swoon of the A.I. revolution before it firmly takes hold.
From Slate • Feb. 8, 2026
A bystander reported that Fischer had said, “Too early,” but Geller’s face turned red, suggesting that Fischer’s reply had been more caustic.
From "Endgame" by Frank Brady
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
