the act of removing something or someone by means of stealth
- (military) The process of exiting an area (usually behind enemy lines or in enemy territory).
- (civil engineering) A method for managing storm water runoff.
- (sciences) A filtering out (usually movement of a substance through a barrier).
- (biology) A gradual movement of a substance to exterior (as through cell membrane to extracellular fluid or medium).
- (computing) Covert extraction of data.