Definition of sadness noun from the Oxford Advanced Learner's Dictionary
sadness
noun
ˈsædnəs ˈsædnəs
1[uncountable, singular]the feeling of being sadmemories tinged with sadnessI felt a deep sadness.It is with great sadness that we report the death of James Banks yesterday.2[countable, usually plural]something which makes you sadour joys and sadnesses