To Sag Off

1. (idiomatic) To skive, to not attend school when required to do so.
2. (idiomatic, basketball or lacrosse) To back off from an opponent against whom one is defending.
3. (idiomatic, nautical) To move too far leeward when sailing on the wind.
4. (idiomatic, stock market) To fall in share price.
5. Used other than figuratively or idiomatically: sag off.