caustic

1 of 2

adjective

caus·​tic ˈkȯ-stik How to pronounce caustic (audio)
1
: capable of destroying or eating away by chemical action : corrosive
The chemical was so caustic that it ate through the pipe.
2
: marked by incisive sarcasm
a caustic film review
caustic humor
3
: relating to or being the surface or curve of a caustic (see caustic entry 2 sense 2)
caustically adverb
causticity noun

caustic

2 of 2

noun

1
: a caustic agent: such as
a
: a substance that burns or destroys organic tissue by chemical action
b
: a strong corrosive alkali (such as sodium hydroxide)
2
: the envelope of rays emanating from a point and reflected or refracted by a curved surface

Did you know?

If you have a burning desire to know the origins of caustic, you're already well on your way to figuring it out. Caustic was formed in Middle English as an adjective describing chemical substances, such as lime and lye, that are capable of destroying or eating away at something. The word is based on the Latin adjective causticus, which itself comes ultimately from the Greek verb kaiein, meaning "to burn." In time, caustic was baked into the English language as an adjective describing people or things (such as wit or remarks) that are bitingly sarcastic. Other kaiein descendants in English include cautery and cauterize, causalgia (a burning pain caused by nerve damage), and encaustic (a kind of paint that is heated after it's applied).

Choose the Right Synonym for caustic

caustic, mordant, acrid, scathing mean stingingly incisive.

caustic suggests a biting wit.

caustic comments

mordant suggests a wit that is used with deadly effectiveness.

mordant reviews of the play

acrid implies bitterness and often malevolence.

acrid invective

scathing implies indignant attacks delivered with fierce severity.

a scathing satire

Examples of caustic in a Sentence

Adjective His [Roosevelt's] caustic cousin, Alice Roosevelt Longworth, called him a sissy and a mama's boy. Garry Wills, Atlantic, April 1994
It was Schuyler's gift for satire and his caustic wit that distinguished his writings and led to his nickname, the Black Mencken. Henry Louis Gates, Jr., New York Times Book Review, 20 Sept. 1992
Albert quailed before those caustic pronouncements, he shuddered and blanched and felt his stomach drop like a croquette into a vat of hot grease. T. Coraghessan Boyle, Harper's, October 1987
The chemical was so caustic that it ate through the pipes. She wrote a caustic report about the decisions that led to the crisis.
Recent Examples on the Web
Adjective
After the caustic irony of the Whigs, the sincerity is jarring. Kory Grow, Rolling Stone, 10 Nov. 2023 Meanwhile, Simonyan, who usually reacts on RT with caustic ridicule to information about civilian victims of Russian bombardment in Ukraine, is reacting with horror to similar events in Gaza. Foreign Affairs, 10 Nov. 2023 House Select Committee via AP Her father gave caustic testimony. Jennifer Peltz, Fortune, 8 Nov. 2023 Suffice it to say that his talent for caustic humor, authentic emotion and thoroughly satisfying narrative resolutions continues unabated. Ann Hornaday, Washington Post, 1 Nov. 2023 Robotic equipment removed the weapons’ fuses and bursters before the mustard agent was neutralized with hot water and mixed with a caustic solution to prevent the reaction from reversing. Andrew Demillo, Thomas Peipert, and Dylan Lovan, The Christian Science Monitor, 7 July 2023 The 2024 Republican presidential race is entering a fraught and caustic new phase, as Donald J. Trump’s wide lead remains undiminished, the days until voting begins dwindle and his rivals take aim at each other as much as at him. Maggie Haberman, New York Times, 7 Nov. 2023 Valerie Jarrett, a former senior adviser to Mr. Obama and the chief executive of the Obama Foundation, pointed to the caustic political discourse dominating modern campaigns, saying a unified front was essential. Nick Corasaniti, New York Times, 7 Sep. 2023 Toxie’s weapon of choice is a mop dipped in the same caustic sludge that transformed him, its noxious embers burning green like bioluminescent plankton lighting up the sea at night. Michael Nordine, Variety, 21 Sep. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'caustic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Adjective and Noun

Latin causticus, from Greek kaustikos, from kaiein to burn

First Known Use

Adjective

14th century, in the meaning defined at sense 1

Noun

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of caustic was in the 14th century

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Dictionary Entries Near caustic

Cite this Entry

“Caustic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/caustic. Accessed 2 Dec. 2023.

Kids Definition

caustic

1 of 2 adjective
caus·​tic ˈkȯ-stik How to pronounce caustic (audio)
1
: capable of eating away by chemical action : corrosive
2
: likely to offend or hurt someone's feelings
a caustic remark
caustically adverb

caustic

2 of 2 noun
: a caustic substance (as caustic soda)

Medical Definition

caustic

1 of 2 adjective
caus·​tic ˈkȯ-stik How to pronounce caustic (audio)
: capable of destroying or eating away organic tissue and especially animal tissue by chemical action
silver nitrate and sulfuric acid are caustic agents
caustically adverb
causticity noun
plural causticities

caustic

2 of 2 noun
: a caustic agent: as
a
: a substance that burns or destroys organic tissue by chemical action : escharotic
b
: a strong corrosive alkali (as sodium hydroxide)

More from Merriam-Webster on caustic

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