the fact or state of being overly absorbed in oneself or extremely conceited, a feeling of self-importance that is excessive or exaggerated;
e.g. Her egotism caused her to become overconfident in the belief that she would easily defeat her opponent.
(noun)
a tendency to think too highly of oneself or to talk too much about oneself, often presenting as the excessive use of first person pronouns (e.g. "I", "me", "my");
e.g. We soon grew tired of his egotism and his constant bragging about his achievements.