Stealth

Stealth is the act of using secrecy or sneakily, and/or in such a way that the actions are difficult to detect by others.

This term can also be used to refer to:
 * Stealth Game, a game genre of which the Metal Gear series define, and were one of the earliest games to demonstrate.
 * Stealth Camouflage, an electronic device used to render the user unseen.