10c is a term used for a person that is basicly a border line psychotic or a person that does everything without thinking of the consequences.
10c Originated from a school class in norway where they took all the bad students, the angry ones and stupid students from the whole grade, and put them in too one single class consisting of 26 Noisemakers.
Example; Jimmi; Im gonna jump from this ledge, into that bush!
Frank; yeah... thats real smart! you jump 3 meters down into a thorn bush while your wearing sweat pants. Your just 10c in your mind!