IPA: /ˈiːɡoʊɪst/
KK: /ˈiːɡoʊɪst/
A person who is primarily concerned with their own interests and benefits, often disregarding the needs of others.
He is such an egoist that he never considers anyone else's feelings.
Egoist → It is formed from "ego" (from Latin, meaning I or self) and "-ist" (meaning one who practices or is concerned with). The word "egoist" refers to a person who is primarily concerned with their own interests or self.
Think of 'ego' meaning 'self' — and the '-ist' indicates a person. An egoist is someone who focuses on themselves.