I was going to suggest asking Pandora99 (Donna) but see she is already "OCF Canuck".
I had also heard the term before and wondered what it meant.
A quick google gives so many and varied possibilities but I like this one....
As to the origin of "Canuck," it may have arisen as a blending of "Canadian" and the Inuit (Eskimo) word "inuk,"

History Leukoplakia bx 8/2006 SCC floor mouth T3N0M0- Verrucous Carcinoma.
14 hour 0p SCC-Right ND/excision/marginal mandibulectomy 9/2006, 4 teeth removed, flap from wrist, trach-ng 6 days- no chemo/rad.
6 ops and debulking (flap/tongue join) + bx's 2006-2012.
bx Jan 2012 Hyperkeratosis-Epithelial Dysplasia
24cm GIST tumour removed 8/2013. Indefinite Oral Chemo.

1/31/16 passed away peacefully surrounded by family