IPA: /ˌiːɡoʊˈmeɪniæk/
KK: /ˈiːɡoʊˌmeɪniæk/
A person who is excessively focused on themselves and their own importance.
He is such an egomaniac that he only talks about his own achievements.
Egomaniac → It is formed from "ego" (from Latin, meaning I or self) and "maniac" (from Greek "maniakos", meaning mad or insane). The word describes a person who is excessively preoccupied with their own self or ego, to the point of madness.
Think of 'ego' meaning self, and 'maniac' suggesting madness — this helps you remember that an egomaniac is someone who is madly focused on themselves.