Green’s Dictionary of Slang

(US) small, insignificant.

1896		Ade Artie (1963) 74: This town’s full of a lot o’ two-by-four dubs that’s got into purty fair jobs.
1906		S. Ford Shorty McCabe 137: But say, next time any two-by-four chappy floats in here for a private course, I gets plans and specifications before I takes him on.
1910		Vicksburg Eve. Post 27 Sept. 7/3: The time has passed when a little two-by-four editor can get up and spout off a lot of dope that will be accepted as gospel truth.
1912		C.E. Mulford ‘Hopalong’s Hop’ in Pearson’s Mag. Nov. 🌐 Somebody in this wart of a two-by-nothin’ town is goin’ to run plumb into a big surprise.
1913		J. London John Barleycorn (1989) 76: John Barleycorn whsispering to me that life is big [...] and telling the two-by-four, cut-and-dried conventional world to go hang.
1920		T.H. Kelly What Outfit, Buddy? 35: I used to be a little two-by-four newspaper man.
1927		(con. 1900s) S. Lewis Elmer Gantry 240: You have to deal with a lot of these two-by-four hick preachers, with churches about the size of woodsheds.
1940		W.R. Burnett High Sierra in Four Novels (1984) 335: All the rest of his family were [...] working two-by-four farms or else losing ’em to the bankers.
1944		H. Hunt East of Farewell 67: With their two-by-four laundry you were lucky to get a couple of khaki shirts a week to wear.
1962		(con. WWII) J.O. Killens And Then We Heard The Thunder (1964) 459: In front of a little two-by-four café.
1990		(con. 1930s–60s) H. Huncke Guilty of Everything (1998) 238: Las Vegas in those days wasn’t anything like it is now. It was just a two-by-four town then.