Green’s Dictionary of Slang

(US) the dormitory suburbs of a big city, mass-produced, featureless, sprawling and aesthetically null.

1962		Press Democrat (Santa Rosa, CA) 26 Feb. 5/1: Our new urban areas — our slurbs — are sloppy, sleazy, slovenly, slipshod semi-cities.
1970		N.Y. Times 30 Nov. 41: Cities so choked and ‘slurbs’ so ugly that by comparison the New York-Washington corridor looks almost like a planned development.
1995		Sydney Morn. Herald 15 July 8A/8: Don Gazzard the architect [...] primarily responsible for ‘Outrage’ [...] an attack on ‘slurbs’.
2004		Wisconsin State Jrnl (Madison, WI) 9 Dec. 12/3: ‘You country dwellers, beware of the “slurb”’.