egoistic vs self-seeking

egoistic is not a noun while self-seeking is a noun.

Word	Noun	Adjective	Verb	Adverb
egoistic	No	Yes	No	No
self-seeking	Yes	Yes	No	No

As adjectives, egoistic and self-seeking are synonyms defined as:

egoistic and self-seeking: concerned chiefly or only with yourself and your advantage to the exclusion of others

Other synonyms of egoistic include egocentric, egoistical, self-centered, self-centred, self-serving, selfish.

egoistic (noun)	self-seeking (noun)
	taking advantage of opportunities without regard for the consequences for others

egoistic (adjective)	self-seeking (adjective)
concerned chiefly or only with yourself and your advantage to the exclusion of others	concerned chiefly or only with yourself and your advantage to the exclusion of others