I, etc. won't bite

(one) won't bite (someone)

You have no reason to be afraid of someone; this person is not going to hurt you, so don't be shy about approaching or talking to them. Don't worry, child, I won't bite. I just wanted to give you a message to pass along to your father. This is your Uncle Jack, son. Well, go on and shake his hand, he won't bite you.

I, etc. won’t ˈbite (you)

(humorous) used to tell somebody that they do not need to be afraid of somebody: You should tell your teacher that you don’t understand — she won’t bite you!