abnegation vs selflessness

abnegation and selflessness both are nouns.

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

As nouns, selflessness is a hypernym of abnegation; that is, selflessness is a word with a broader meaning than abnegation:

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

Other hypernyms of abnegation include forgoing, forswearing, renunciation, self-sacrifice.

abnegation (noun)	selflessness (noun)
renunciation of your own interests in favor of the interests of others	acting with less concern for yourself than for the success of the joint activity
the denial and rejection of a doctrine or belief	the quality of unselfish concern for the welfare of others