Don't do that, you silly boy!
a silly mistake
She gets upset over such silly things.
- What's the name of that guy on TV - you know, the American one with the silly voice?
- They can't expect me to accommodate all their silly little likes and dislikes.
- Why are you putting on that silly voice?
- I screamed myself silly on the roller coaster.
- Seriously now, did he really say that or are you just being silly?
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