To jump bail is to basically leave the state, country, or dissapear before your court date after you have posted bail. This means that you are stealing money from the person that has posted your bail. (A bail bondsmen) Normally you would be released from jail, then go to court. After your trial the bail bondsmen will have his money returned. This means that he has the right to track you down. You may even be accused of jumping bail before you even miss a court date. This is usually because you might be planning to leave or have already left. Once found after jumping bail, you will be thrown in jail until you appear in court, afterwhich the bail bondsmen will have his money returned; jumping over a hay bale.
John posted bail then fled
the country to Mexico. What a flake
! He totally jumped bail
!; Look, Ryan just jumped the bail! He's the coolest!; to jump bail
is really lame
; to jump the bail is radical.