strung up

Hi, I checked a few dictionaries and they say "string someone up" means to kill someone by hanging them by the neck using a rope.

But according to the dictionary below, it can be used as punish someone severely, which is just a punishment, not killing. May I know whether this is the case? Thank you.

string someone up

The dictionary is confusing two things: what the idiom means, and how it is sometimes used in a figurative or exaggerated manner. It's the same as when you tell a friend (jokingly) that you're going to kill him if he's late for a meeting. "Kill" means murder / cause to die, but you don't literally mean you will do that.