1. the quality or state of being rigid, hard to bend, or lacking flexibility
Usage: plural of stiffness
2. the quality of being formal, awkward, or lacking ease in manner or movement
Usage: plural of stiffness

Examples

• The different stiffnesses of the materials made some easier to work with than others.
• After sitting for hours, he felt various stiffnesses in his neck and back.
• The yoga instructor helped students work through their muscle stiffnesses.
• Engineers tested the stiffnesses of several metal alloys.
• Her social stiffnesses made it difficult for her to make friends.
• The dance teacher worked to eliminate the stiffnesses in their movements.