This word probably means two things... First being the dreaded meaning of failure and death, Skeletor is a good example. Or perhaps it means the most kick-ass first-person shooter that was the grandfather of the genre, a masterpiece by Id and John Romero...
Recently I re-kindled the area of my brain reserved for Doom and also Hexen: Beyond Heretic which is Doom if it ever made out with dark fantasy, big burly warriors, demons, axes that light on fire... Yeah, that stuff. Finding Hexen was easy enough since it was released later than Doom II, though Doom II was a bit difficult, but I found it nonetheless. Since it was classified as a DOS game, became hard to play since most PC's run Vista and 7. So I went searching some more and stumbled onto GZDoom, an external engine that has OpenGL support and has a MUCH higher quality and speed on more recent systems, so playing Hexen again, not with pixels as everything, but full 3D and more brutality.
Then I found Brutal Doom, a modification (I don't even know how this guy's team managed to mod a DOS/95 game...) and it's a slug shooting, gut ripping, body perforating, blood gushing game. If you want to see a bit more, it's awesome, but I will warn you...
THIS MOD CONTAINS GRATUITOUS AMOUNTS OF BLOOD AND GORE
http://www.youtube.com/watch?v=samQ-Xxc1M4
There's some considerable amount of downloading to be done, namely GZDoom for the execution on later machines and OS's, Doom 95 for the actual thing, Brutal Doom if you want to complete your life and the re-mixed soundtrack which is entirely optional, but MIDI music will NOT satiate brutality.