egocentric vs egoistical

egocentric is a noun but egoistical is not a noun.

Word	Noun	Adjective	Verb	Adverb
egocentric	Yes	Yes	No	No
egoistical	No	Yes	No	No

As adjectives, egocentric and egoistical are synonyms defined as:

egocentric and egoistical: concerned chiefly or only with yourself and your advantage to the exclusion of others

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

egocentric (noun)	egoistical (noun)
a self-centered person with little regard for others

egocentric (adjective)	egoistical (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