Green’s Dictionary of Slang

1. (orig. Can.) a Newfoundlander; also attrib.

1958		Eve. Telegram (St. John’s, Newfoundland) 8 May 4/5: Of course he couldn’t have passed me [...] the ill bred Newf that I am [OED].
1972		Calgary Herald (Alberta) 11 Mar. 33/1: Newfie stole a single in the seventh [...] with Squid Jiggers sitting three.
1974		M. Cherry On High Steel xiv: The Newfies are often hockey freaks.
1978		Maledicta II:1+2 (Summer/Winter) 163: Newfie Anyone from Newfoundland. Newfie jokes are in Canada what Polack jokes are in the United States, since Newfoundlanders are considered notoriously stupid and backward due to their isolation from urban centers. The world’s slowest railroad, serving Newfoundland for over a century, was nicknamed ‘The Newfie Bullet’.
2003		N. Green Angel of Montague Street (2004) 14: They’d tell Newfie jokes [...] ranking on people from Newfoundland because they talk funny.

2. (US) Newfoundland.

1977		J. Langone Life at the Bottom 74: The Coast Guard and the pipeliners and them pussy-stripers up in Newf.
1984		(con. WW2) T. Jones Heart of Oak [ebook] On one convoy , ON5, en route to Newfie, we passed another, SC128, bound from Newfie.

3. (US) a Newfoundland dog.

1977		Time (Atlantic edn) 5 Sept. 51/3: Newfs are ... strong swimmers whose webbed front paws arc out in a powerful breast stroke.
2004		Newf Rescue 🌐 Any pure breed Newfoundland [...] is immediately taken to one of our participating veterinarians for a complete health check [...] The Newf is then placed into one of our foster homes for an undetermined length of time.