Noclip

Noclip mode, short for "no clipping" mode, is a state in computer and video games whereupon the player's character is granted the ability to walk through walls and other obstacles. Such a state is usually enabled by means of a cheat code.

First-person shooters are the games that most often contain these cheats, having originated in Wolfenstein 3D and Doom. Quake-engine games and their derivatives (such as Half-Life and its mods) usually grant the player's character flight as well when noclip mode is enabled.