IPA: /ˌiːɡəʊˈɪstɪkəl/
KK: /iˈɡoʊɪstɪkəl/
Focusing on oneself and one's own interests, often to the exclusion of others.
His egotistical behavior made it hard for him to maintain friendships.
Egoistical → It is formed from "ego" (from Latin "ego", meaning I or self) and "-istical" (a suffix used to form adjectives). The word "egoistical" describes a person who is focused on themselves or their own interests.
Think of 'ego' as representing the self, and remember that 'egoistical' means someone who is very focused on their own interests.