swellhead
/ˈswɛlˌhɛd/
noun
- A person who is overly proud or conceited, often showing off their own importance.
- She's a bit of a swellhead, always bragging about her grades in front of the class.
- The coach warned the team not to let the victory turn them into swellheads.
- After winning the award, he became such a swellhead that nobody wanted to work with him.