Self-important (adjective)

Having an excessive sense of self-importance.

Origin:

Combination of self and important, meaning having an excessive sense of self-importance.

Examples:

1. He was self-important and believed that his opinions were the only ones that mattered.
2. She was self-important and always had to be the center of attention.
3. He was so self-important that he didn't even listen to others.
4. She had a self-important attitude and was always looking down on others.
5. He had a tendency to become self-important when he was given a little bit of power.