Definition & Meaning of "set (the) alarm bells"

What is the origin of the idiom "set alarm bells" and when to use it?

The exact origin of the idiom "set alarm bells" is not well-documented, but it likely stems from the association of alarm bells with alerting or warning people to potential danger. Bells have been used throughout history as signals to indicate emergencies or threats, and the phrase "set alarm bells" figuratively extends this concept to situations that warrant attention or caution. It is used to describe a situation or action that triggers a sense of warning, concern, or suspicion. It often signifies that a potential problem, danger, or issue has been identified, prompting people to take notice and investigate further.