In simple terms, it means that you don’t take your vacation and keep your vacation balance to get paid out at the end of the year, or just keep it in the bank if you want to drop a trip (if you can) and use vacation balance to get credit for said trip.

The union advised all AA pilots to take their vacation in order to “recover/unwind” from their stressful schedules. One can connect the dots on what that means, but it’s pretty clear to everyone, including those who ignored the union.