acid test

American  

noun

1. a severe and conclusive test to establish quality, genuineness, worth, etc.

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acid test British  

noun

1. a rigorous and conclusive test to establish worth or value

   the play passed the critic's acid test

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acid test Idioms  

1. A decisive trial to determine worth or quality, as in Exposure to brilliant sunlight is the acid test for showing this fabric won't fade. Alluding to a 19th-century chemical test for distinguishing gold from other metals, this term was used figuratively by the early 1900s.

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Etymology

Origin of acid test

First recorded in 1890–95

Example Sentences

They've been far from the acid test of Scotland's true worth.

From BBC • Feb. 13, 2026

"This was the real acid test here against a team motivated to win and the holders of the competition," he insisted.

From Barron's • Jan. 28, 2026

Single stair, and the fate of Culver City’s ordinance specifically, represents an early California acid test.

From Los Angeles Times • Nov. 23, 2025

“I think this is going to be the acid test for Morena,” said sociologist Bernardo Barranco.

From Washington Times • Nov. 10, 2023

In chemistry and physics the acid test of one’s understanding of a system is whether one can successfully predict its future behavior.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond