A shorting for Newfoundlander. Newfoundland is the most eastern province in Canada. Newfies speak Newfoundland English which is a mix of several accents and dialects of English. But remember some Newfoundlanders don't like being called Newfies by Americans or sometimes other Canadians.
Person 1: So you're from Newfoundland?
Person 2: Yep, I'm a Newfie.