-ness — state, quality, condition of being (affix)

happiness A2

/ˈhæpinɪs/ The feeling of being happy; joy. M S

darkness B1

/ˈdɑɹknɪs/ The state of having little or no light. M S

illness B1

/ˈɪl.nəs/ The state of being sick or in bad health. M S

weakness B1

/ˈwik.nɪs/ The state of not being physically or mentally strong. M S

kindness B1

/ˈkaɪnd.nəs/ The quality of being kind, caring, and generous toward others. M S

sadness B1

/ˈsædnəs/ The feeling of being unhappy. M S