'Dead ashes reignite' is a vivid idiom describing the unexpected resurgence of something previously thought extinguished—such as a conflict, rivalry, emotion, or problem. Literally, 死 (sǐ) means 'dead', 灰 (huī) 'ashes', 复 (fù) 'again', and 燃 (rán) 'to burn'. Together, they evoke the image of cold, lifeless ashes suddenly bursting back into flame—an apt metaphor for dormant forces reawakening with intensity.

This idiom is commonly used in formal or literary contexts to describe the revival of negative or troublesome phenomena: long-dormant tensions between groups, a relapse in illness, the return of an old grudge, or even the resurgence of outdated ideas. It carries a distinctly cautionary or critical tone, implying that the 'reignition' is undesirable and potentially dangerous. While rooted in classical Chinese, it remains current in modern media, political commentary, and literature.