kaku-kaku
Describes stiff, jerky joint movements — like a robot. Knees or elbows that don't bend smoothly, often from age or overexertion.
💡After sitting too long — 'My knees are kaku-kaku when I try to stand up.'
長時間座ったあと、膝がかくかくする。
After sitting for hours, my knees move kaku-kaku stiffly.
My joints felt ___ and stiff after the long car ride.
長いドライブのあと、関節が○○する。