Dippy (adjective)

1. Silly or foolish in behavior or appearance.
2. Acting in a crazy or unpredictable way.

Origin:

The origin of this word is uncertain, but it is believed to have originated in the late 19th century.

Examples:

1. She's a bit dippy, but she means well.
2. The new teacher is a bit dippy, but the kids seem to like her.
3. He's acting really dippy today.
4. The weather is a bit dippy, it's hot one minute and cold the next.
5. She"s a dippy, she"s always forgetting things.