When you vamoose, you exit quickly. If you're feeling overwhelmed by the loud music and crazy dancing at your friend's party, you might decide to vamoose without saying goodbye to her.
If your grandfather's clearly getting ready to tell the family a long, boring story, you and your cousin might vamoose. Your little brother might prefer to stay at a birthday party long enough to whack the pinata but vamoose before the birthday boy starts opening gifts. In either case, someone leaves suddenly, and somewhat stealthily. Vamoose has been around since the mid-nineteenth century, from the Spanish word vamos, or "let's go!"