leet = 1337 = 1+3+3+7 =14 so you have to be 14 to be it.
This a name/title for a newbie hacker who thinks he knows his shit but really doesn't. I am saying this on personal experiance; everyone who has called them self leet/1337 ended up being complete idiots who can't hack without a downloaded program and/or they don't even know what a hacker is.