420 is the section number in the Indian Penal Code (enacted in 1860) that refers to the offense of cheating. Punishment for this cognizable offense is one to seven years in prison and/or a fine.
"420. Cheating and dishonestly inducing delivery of property.
Whoever cheats and thereby dishonestly induces the person deceived to deliver any property to any person, or to make, alter or destroy the whole or any part of a valuable security, or anything which is signed or sealed, and which is capable of being converted into a valuable security, shall be punished with imprisonment of either description for a term which may extend to seven years, and shall also be liable to fine."1
At NJIT, the term 420-ing is often heard after physics and math exams, as in, "so and so were 420-ing so hard". Respective faculty departments have attempted to implement additional proctors and an updated Honor Code that stressed more responsibility in individuals. Residence Assistants and faculty hung posters with the new code on the walls throughout dormitory hallways and classrooms. Ironically, the bottom of each poster indicated that the code was heavily adapted from that of another university.
1The Indian Penal Code. http://www.indialawinfo.com/bareacts/ipc.html.