unbreakable
adj.adj. impossible to break or destroy. You use this to describe things that are very strong or relationships that cannot be ruined.
adj. incapable of being broken, fractured, or destroyed. Often used figuratively to describe abstract concepts like bonds, spirits, or records.
The screen is made of unbreakable glass.
After twenty years of working together, the two business partners shared an unbreakable bond of trust.
The athlete set an unbreakable record that stood for decades, defying every attempt by younger competitors to surpass his legendary performance.
From un- + break + -able.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Typically used as a gradable adjective, though in a strict physical sense it functions as an absolute quality.
Last updated May 8, 2026