self-interest vs opportunism

self-interest and opportunism both are nouns.

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

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

self-interest and opportunism: taking advantage of opportunities without regard for the consequences for others

Other synonyms of self-interest include expedience, self-seeking.

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