E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
To be off, to decamp, to escape. A curious instance of argot. Canille is old French for chenille, a pupa, imago, or chrysalis. These afterwards become winged insects and take their flight. So a visitor says in France, Il faut me sauver, or Il faut decaniller. I must be off.