Boo-boo (noun)

1. A minor mistake or error.
2. A minor injury, such as a cut or scrape.
3. An embarrassing or foolish act.

Origin:

Of imitative origin.

Examples:

1. She made a boo-boo on her math homework and had to redo it.
2. He fell off his bike and scraped his knee, but it was just a minor boo-boo.
3. The team's loss was a real boo-boo, but they were determined to bounce back.
4. He made a boo-boo in front of the whole class, but he laughed it off.
5. He said it was a simple boo-boo, but it was a serious mistake.