This phrase leads us to another one: “I’m in”. To be “in” or “out” means you decided you are going to be part of a certain situation. You’re not asking for permission (as in “I want in”), you’re just telling the people what you’ve already decided.
For example, a group of friends are planning to get into some kind of mischief. Before they start, the leader says, “If anyone wants out, there’s the door.” One of them decides he doesn’t want to be part of it, so he says “I’m out, sorry guys”.
Well, that’s for this week.
Hope you learned something!