selflessness vs denial

selflessness and denial both are nouns.

Word	Noun	Adjective	Verb	Adverb
selflessness	Yes	No	No	No
denial	Yes	No	No	No

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

selflessness: acting with less concern for yourself than for the success of the joint activity
denial: renunciation of your own interests in favor of the interests of others

Other hyponyms of selflessness include abnegation, self-abnegation, self-denial, self-renunciation.

selflessness (noun)	denial (noun)
acting with less concern for yourself than for the success of the joint activity	a defendant's answer or plea denying the truth of the charges against him
the quality of unselfish concern for the welfare of others	renunciation of your own interests in favor of the interests of others
	the act of refusing to comply (as with a request)
	the act of asserting that something alleged is not true
	(psychiatry) a defense mechanism that denies painful thoughts