selflessness vs cooperation

selflessness and cooperation both are nouns.

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

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

selflessness: acting with less concern for yourself than for the success of the joint activity
cooperation: joint operation or action

selflessness (noun)	cooperation (noun)
acting with less concern for yourself than for the success of the joint activity	joint operation or action
the quality of unselfish concern for the welfare of others	the practice of cooperating