To show off means to deliberately draw attention to your abilities, possessions, or accomplishments to impress others. When someone shows off, they might perform cartwheels in the middle of the playground when everyone's watching, or talk loudly about the expensive sneakers they're wearing, or keep mentioning how they got a perfect score on yesterday's quiz.

Showing off often backfires because people can tell when someone is trying too hard to impress them. There's a difference between being proud of something you've worked hard for and constantly reminding everyone how great you are. A gymnast who practices a difficult move and finally nails it has every reason to feel proud. But if she keeps doing that move over and over just to make sure everyone sees how talented she is, she's crossing into showing off territory.

Sometimes people use the phrase as a compliment, though. A proud parent might say, “Show off your piano skills for Grandma!” In this case, it means demonstrating something you've learned, not bragging about it.

The word show-off (with a hyphen) works as a noun for someone who shows off frequently. A show-off can make conversations and activities feel like competitions that nobody asked to join.