Why is the term boo-boo related to an injury?

The term "boo-boo" is believed to have originated as a euphemism for the word "booby", which was used in the 17th century to refer to a foolish or stupid person. Over time, the term "booby" came to be used in a more general sense to refer to a minor injury or mishap, and the term "boo-boo" eventually developed as a variant of "booby" specifically in this context.

The use of "boo-boo" as a term for an injury is likely due to its playful and non-threatening nature. It is often used in a light-hearted manner to refer to minor injuries, particularly when speaking to children, in order to minimize the seriousness of the situation and provide comfort.