C1 noun /ˈiːɡoʊˌɪzəm/
egoism
利己主義
Meaning
An ethical theory that treats self-interest as the foundation of morality; also, excessive preoccupation with oneself.
Example
His decisions were often driven by egoism rather than concern for others.
彼の決断はしばしば他人への配慮よりも利己主義に駆り立てられていた。