Stealth video games involve you using covert movement, hiding behind objects and managing how much sound you are making to get to a destination without being detected by computer or human players.
You have to avoid line-of-sight of enemy players to successfully sneak past. Some games also require you to minimise the noise you are making, or to move slower, to get passed undetected.
Some stealth games combine other genres. Shooting or Adventure games often have the option of approaching an objective with either stealth or direct attacking. Platform games and Turn-Based games often let you use stealth to avoid engaging enemies.
Games with stealth is the primary (and sometimes only) option pit you in espionage, counter-terrorism, and special forces situations. Quite often stealth it used in games to get the upper hand to then switch to a more violent or aggressive approach to perform spying, stealing or assassinations.