alarm bell

noun

: a bell that sounds when an alarm is activated

—often used figuratively

… the Mexican swine flu outbreak that is sounding alarm bells [=causing people to become worried or alarmed] across the world …

—Andres Oppenheimer, Miami Herald, 30 Apr. 2009

The spike in oil prices has set off alarm bells across the automobile industry.

Word History

First Known Use

1548, in the meaning defined above

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