litmus test

noun

: a test in which a single factor (such as an attitude, event, or fact) is decisive

Did you know?

Litmus Test Has Scientific Origins

It was in the 14th century that scientists discovered that litmus, a mixture of colored organic compounds obtained from lichen, turns red in acid solutions and blue in alkaline solutions and, thus, can be used as an acid-base indicator. Six centuries later, people began using litmus test figuratively. It can now refer to any single factor that establishes the true character of something or causes something to be assigned to one category or another. Often it refers to something (such as an opinion about a political or moral issue) that can be used to make a judgment about whether someone or something is acceptable or not.

Examples of litmus test in a Sentence

The party is using attitudes about gun control as a litmus test for political candidates.

Recent Examples on the Web

To pull a private letter from Jefferson and then try to apply it as some sort of constitutional litmus test is really, really poor judgment in my opinion. —Kayla Dwyer, IndyStar, 12 Nov. 2025

Over the next year, there will also likely be primaries from the left and expect the shutdown positioning to be a litmus test for those primaries – and for 2028. —Domenico Montanaro, NPR, 11 Nov. 2025

The results could signal a shift in where the country is politically, acting as a litmus test ahead of the 2026 midterm elections. —Marni Rose McFall, MSNBC Newsweek, 5 Nov. 2025

The recall was widely seen as a litmus test for how much clout the national conservative group can wield in non-partisan local politics. —Maritza Dominguez, AZCentral.com, 4 Nov. 2025

Word History

First Known Use

1913, in the meaning defined above

Rhymes for litmus test

• acquiesced
• coalesced
• dispossessed
• manifest
• overdressed
• overstressed
• prepossessed
• reassessed
• reinvest
• repossessed
• unaddressed
• uncompressed

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