strong-backed; having a strong lower back
Literally describes a physically strong lower back or core; can also imply physical resilience.
He has a strong back and can lift heavy loads with ease.
stubborn; persevering; tenacious
Figurative use: describes a person who is mentally tough, unyielding, or persistent, like having a strong 'backbone'.
viscous; elastic and sticky; chewy
Describes a texture that is thick, sticky, and stretchy, like mochi or certain doughs. This sense is less common and may be regional or specialized.
She is tenacious and sees through whatever she decides to do.
This mochi is chewy and has a satisfying texture.
Compound of 腰 (こし, 'lower back, hips') and 強 (つよ, stem of 強い 'strong'). The figurative senses derive from the idea of having a strong 'backbone' or core.