diplomacy vs tactfulness

diplomacy and tactfulness both are nouns.

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

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

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

Other hypernyms of diplomacy include tact.

diplomacy (noun)	tactfulness (noun)
subtly skillful handling of a situation	consideration in dealing with others and avoiding giving offense
wisdom in the management of public affairs	Behavior or actions characterized by careful consideration in dealing with others, to avoid giving offense.
negotiation between nations