Definition of "Stiffness" :

noun: excessive sternness

noun: the inelegance of someone stiff and unrelaxed (as by embarrassment)

noun: firm resoluteness in purpose or opinion or action

"A charming host without any touch of stiffness or pomposity."

noun: the property of moving with pain or difficulty

"He awoke with a painful stiffness in his neck."

noun: the physical property of being inflexible and hard to bend