noun
- a harbinger of the end, death, or destruction of something.
- passing bell.
noun
- something that heralds death or destruction
- a bell rung to announce a death
Something that indicates impending failure, as in His low scores sounded the death knell for his ambitions. The noun knell, used for the ringing of a bell since at least a.d. 1000, is rarely heard today except in this figurative phrase.