1. To leave a place quickly, suddenly, and/or inconspicuously. The lecture was so boring that I just dipped out when the professor wasn't looking.

2. To miss out on or choose not to participate in something. (Usually followed by "on.") Primarily heard in Australia, New Zealand. Many students end up dipping out on government funding for third-level education because they simply don't understand the application process. I think I'll dip out on that party this evening, I'd rather just stay at home.

3. To fail an exam or course at school. Primarily heard in Australia, New Zealand. Jonathan was eager to leave school, but he dipped out in his final exams and had to repeat the year.

4. To exit due to a failure to advance, as from a sports tournament. Though heavily favored to win the championship for a third straight year, the team dipped out after only the second round.