1. To accompany one to the exit from a room or building. (Sometimes seen as "show (one) to the door.") Thank you so much for coming in for the interview. John, would you please show Mr. Porter the door?

2. To escort or forcibly remove one from a building, typically due to some violation of the rules. Sir, if you don't calm down, I'm afraid I'll have to show you to the door.

3. By extension, to fire one from a job. I'll let you off with a warning this once, but if you ever show up to work smelling of alcohol again, I'll show you the door so fast it will make your head spin.