discreetness vs tactfulness

discreetness and tactfulness both are nouns.

Word	Noun	Adjective	Verb	Adverb
discreetness	Yes	No	No	No
tactfulness	Yes	No	No	No

As nouns, tactfulness is a hypernym of discreetness; that is, tactfulness is a word with a broader meaning than discreetness:

discreetness: subtly skillful handling of a situation
tactfulness: consideration in dealing with others and avoiding giving offense

Other hypernyms of discreetness include tact.

discreetness (noun)	tactfulness (noun)
subtly skillful handling of a situation	consideration in dealing with others and avoiding giving offense
knowing how to avoid embarrassment or distress	Behavior or actions characterized by careful consideration in dealing with others, to avoid giving offense.