tact vs discreetness

tact and discreetness both are nouns.

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

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

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

tact (noun)	discreetness (noun)
consideration in dealing with others and avoiding giving offense	subtly skillful handling of a situation
	knowing how to avoid embarrassment or distress