late 15th century: from Anglo-Norman French, from torture 'torture'
Tortuous and torturous have different core meanings. Tortuous means ‘full of twists and turns’ or ‘devious, circuitous’: both paths were tortuous and strewn with boulders. Torturous is derived from torture and means ‘involving torture or excruciating pain’. Torturous should be reserved for agonized suffering; it is not a fancy word for ‘painful’ or ‘discomforting,’ as in I found the concert torturous because of the music’s volume.