expedience vs selfishness

expedience and selfishness both are nouns.

Word	Noun	Adjective	Verb	Adverb
expedience	Yes	No	No	No
selfishness	Yes	No	No	No

As nouns, selfishness is a hypernym of expedience; that is, selfishness is a word with a broader meaning than expedience:

expedience: taking advantage of opportunities without regard for the consequences for others
selfishness: stinginess resulting from a concern for your own welfare and a disregard of others

expedience (noun)	selfishness (noun)
the quality of being suited to the end in view	stinginess resulting from a concern for your own welfare and a disregard of others
taking advantage of opportunities without regard for the consequences for others