From Longman Dictionary of Contemporary Englisha/the sword of Damoclesa/the sword of DamoclesliteraryKILL a bad thing that might happen at any timeThe treaty hung like a sword of Damocles over French politics. →sword
Examples from the Corpus
a/the sword of Damocles• Indeed, a wingeddagger was the S.A.S. badge, originally conceived, it is said, as the sword of Damocles.• It's been hanging over my head like the sword of Damocles.