alarm bell

Noun

alarm bell (plural alarm bells)

1. (figuratively, plural-normally) A sudden awareness of danger.
   • The specter of women in factories, women in schoolrooms, and women attending — a lot less addressing — public meetings set off alarm bells in the South.1998, Michele Gillespie, Catherine Clinton, Taking off the white gloves: Southern women and women historians
   • I only got a glimpse of him, but alarm bells went off. He wasn't rushing over to give me a pat on the back for stopping to help.2010, John M Findley, Just Lucky
2. Used other than figuratively or idiomatically: see alarm, bell.
   • He put his foot on a concealed button under his desk and rang an alarm bell. He always had two strongarm men lolling around in an office down the passage.2000, James Hadley Chase, An Ear to the Ground