The word "cant" can mean more than one thing:

1. Cant is insincere speech, similar to hypocrisy. The difference between the two is sometimes explained thus: the hypocrite is entirely cynical and doesn't even believe the snake-oil he or she is expounding; while the speaker of cant does have conceptual faith in what he or she says—but won't actually be practicing what he or she is preaching.
2. Canting is an old word for punning in heraldry. For example, a person named Connington might have a rabbit (a coney) and a barrel (a tun) on his coat of arms. See Rebus.
3. Cant is often used in instant messaging as a shorter form of the contraction can't.
4. Cant is term for a secret language, a cryptolect.
5. Cant on a road or railway is the difference in elevation of the two sides of the track to help go around curves.
6. Cant is an edge, border, nook, or angle. This use of the word likely derives from Old French and is the basis for the term canton.