Green’s Dictionary of Slang

pompous, self-satisfied.

1927		B. Cormack Racket Act I: Keep your hands off me, you stuffed shirt bastard!
1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 472: His glance caught two men, one with a shiny face and stuffed appearance.
1955		B. Schulberg On the Waterfront (1964) 13: A bunch of stuffed-shirt hypocrites.
1961		G.L. Coon Meanwhile, Back at the Front (1962) 16: Mr. Andover, bloated and bilious, stuffed shirt, complexes and all.
1973		P. Driscoll Wilby Conspiracy (1991) 48: A stuffed-shirt Afrikaner, full of correctness and self-importance.
1985		(con. 1968) D.A. Dye Citadel (1989) 157: I probably should have let that stuffed-shirt sonofabitch cart you away to the brig.
2005		L. Redhead Rubdown [ebook] I’m sneaking around videoing her for her stuffed-shirt father and feeling like a supergrass.