This bread has just the right firmness.
Measure the hardness of the metal.
honesty; integrity; uprightness
Only when written 堅さ
Metaphorical use referring to a person's character: being principled, honest, or unwavering. Often written 堅さ in this sense.
Everyone acknowledges his integrity.
We measure the hardness of this rubber.
As it cooled, the chocolate became harder.
Perhaps out of nervousness, his expression showed some stiffness.