… Like “amscray,” “cheese it,” or “beat it,” “23 skidoo” is an American slang phrase dating from the early part of the 20th century that is associated with leaving a difficult, dangerous, or tricky situation quickly.
For example: ”Let’s 23 skidoo before the cops come!” Or: “Hey, youse two … 23 skidoo! I don’t wanna see yer mugs in this saloon no more.”