1812, "full of dots," from dot (n.) + -y (2). Meaning "silly" is from c. 1400, in dotypolle "dotty poll" (i.e. "dotty head"), in which case the first element is from dote (v.).
权威例句
1. She was obviously going a bit dotty.
她显然变得有点疯疯癫癫的了。
2. That's my dotty points.
那是我的弱点.
3. I freely confess I'm as dotty as you are.
我坦白承认,我跟你一样疯疯癫癫.
4. Not another of your dotty ideas for making money!
你不要再出那些赚钱的馊主意了!
5. He did not look like a ghost, more like someone's dotty father.