1. having an excessively high opinion of oneself; conceited or arrogant
Usage: informal

Examples

• After winning the championship, he became swellheaded and started bragging constantly.
• Don’t get swellheaded just because you got one good grade.
• Her swellheaded attitude made it difficult for her to make friends.
• The coach warned the players not to become swellheaded after their victory.
• His swellheaded behavior at work annoyed his colleagues.
• She was talented but not swellheaded about her abilities.