self-interest vs egocentrism

self-interest and egocentrism both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-interest	Yes	No	No	No
egocentrism	Yes	No	No	No

As nouns, self-interest and egocentrism are synonyms defined as:

self-interest and egocentrism: concern for your own interests and welfare

Other synonyms of self-interest include egoism, self-centeredness, self-concern.

self-interest (noun)	egocentrism (noun)
concern for your own interests and welfare	concern for your own interests and welfare
taking advantage of opportunities without regard for the consequences for others