tactfulness vs thoughtfulness

tactfulness and thoughtfulness both are nouns.

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

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

tactfulness: consideration in dealing with others and avoiding giving offense
thoughtfulness: kind and considerate regard for others

Other hypernyms of tactfulness include considerateness, consideration.

tactfulness (noun)	thoughtfulness (noun)
consideration in dealing with others and avoiding giving offense	a considerate and thoughtful act
Behavior or actions characterized by careful consideration in dealing with others, to avoid giving offense.	the trait of thinking carefully before acting
	kind and considerate regard for others
	a calm, lengthy, intent consideration