When I was 6, I used to think the term "dummy" was a curse word. So I felt really grown-up and cool calling someone "dummy".
A childhood belief about swearing

others believed things like this
- i used to think that the word "stupid" was a curse word, ranging in scale right beside the "f" word.Anon
- I thought "sake" was a curse word— shh
- I used to believe that grown-ups were born "grown up" and that I would stay a little kid forever.— Still A Kid
- I thought grown ups were born grown ups.— mea
- I used to think you had to get special permission from your parents to use curse words— zeitgeist
- I used to believe that grown-ups were born grown up.— Juleen