the.com/toughness

means The quality of enduring strain, hardship, or damage without giving way — or of recovering fast when you do.

from From 'tough,' tracing back to Old English 'tōh,' meaning able to bend, grip, or resist without tearing — the word originally described sticky, pliable materials, like a tough cord of leather or a wad of adhesive clay. It's related to Old High German 'zāhi,' with the same sense of cohesive, stretchy resistance. The physical image of something that bends under pressure without snapping is still buried in the modern, more emotional sense — toughness was never about hardness, but about elasticity under load.