Egotistical (adjective)

Excessively self-centered and self-absorbed; having an inflated sense of one's own importance.

Origin:

Early 19th century: from egotism + -ical.

Examples:

1. He was criticized for being egotistical.
2. The egotistical behavior was seen as arrogant.
3. Egotistical people often lack humility.
4. Egotistical behavior can be detrimental to relationships.
5. Egotistical thinking can lead to poor decision making.