Bookout
The process of closing out a position in a swap contract or another OTC derivative agreement prior to maturity.
Investopedia Commentary
The position is closed by taking an offsetting position (i.e. taking a short position if you're long) in the same contract or by paying the opposite party the market value of the swap agreement.
See also: Delivery Date, Fungibility, Maturity, Offset, OTC, Swap