Dotty (adjective)

1. Slightly crazy or eccentric.
2. Slightly absent-minded or forgetful.

Origin:

From the word "dot" meaning a small round mark or spot.

Examples:

1. She"s a bit dotty, but she"s harmless.
2. He"s a bit dotty, but he"s always been like that.
3. The old lady was considered dotty by her neighbors.
4. The dotty professor would often forget where he put his keys.
5. The dotty artist's paintings were considered eccentric but brilliant.