Green’s Dictionary of Slang

Canuck n.

also Canack, Canacker, Cannock, Conuck, Cunnock, Cunnuck, Jack Canuck, Kanacka, Kanaka, Kanuck, Kanuk, Knuck
[Can. Fr. canaque, f. Hawaiian kanaka, a man or simply Can(ada) + (chin)ook. The term supposedly originated in the Maine lumber camps; as regards derog. status, note email, to American Dialect Society List 4/8/99: ‘“Canuck” is not in the least offensive, as Canadian linguists and lay folk have told me. Note the hockey team, the Vancouver Canucks’]

(US) a derog. term for a Canadian, esp. a French Canadian.