Adding the suffix -ness
goodness
sadness
bitterness
foolishness
kindness
softness
illness
madness
fitness
plainness
stillness
quietness
darkness
coldness
hardness
Adding the suffix -ness
goodness
sadness
bitterness
foolishness
kindness
softness
illness
madness
fitness
plainness
stillness
quietness
darkness
coldness
hardness