My little brother used to believe that the 'bat man' dance (where you streak two fingers across each eye) was a swear word. My other brother and I used to walk up to him and do it all the time just to get him to think we were swearing at him.
He also believed that teenagers were people that walked around in trench coats and flashed everyone.
A childhood belief about swearing

others believed things like this
- I used to believe that swearing was just saying, “I swear!”Anon
- My friend believed that when lightening flashed, you better smile because God was taking your picture! — Linda from Southern California
- i used to think the word "suck" was a swear wordAnon
- My brother told me one time that sex was when 2 people were naked drinking a coke from the same bottle.— Danielle
- I used to believe that bizarre was a swear word.Anon
- I used to believe that “shut up” was a swear word.Anon