tact vs diplomacy

tact and diplomacy both are nouns.

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

As nouns, diplomacy is a hyponym of tact; that is, diplomacy is a word with a more specific, narrower meaning than tact:

Other hyponyms of tact include delicacy, discreetness, finesse, address, savoir-faire, tactfulness.

tact (noun)	diplomacy (noun)
consideration in dealing with others and avoiding giving offense	subtly skillful handling of a situation
	wisdom in the management of public affairs
	negotiation between nations