Green’s Dictionary of Slang

1. (Aus.) one who lives in the western suburbs of Sydney; also attrib.

1985		Tracks (Aus.) May 5: I happen to live in the Blue Mountains and I enjoy the travel and clean-air but I don’t enjoy such gems as Piss off westies, so how about a fair go? [Moore 1993].
2007		D. McDonald Luck in the Greater West (2008) 109: There were plenty of westie guys about.

2. (Aus.) one who totally lacks fashion sense.

2001

Sydney Morning Herald (Aus.) 6 Jan. n.p.: So here’s a tentative guide to Sydney teenspeak: [...] Westie (a really bad dresser).

3. (N.Z.) one who lives in the western suburbs of Auckland.

2003

McGill Reed Dict. of N.Z. Sl. 228: Westie Inhabitant of western suburbs of Auckland, perceived as rough beer drinker in tight black jeans driving a beaten up Holden ute. Those who adopt this image are said to be Westicated.