Green’s Dictionary of Slang

1. a general derog. term addressed to a fat person.

1947		S.J. Perelman ‘How Sharper Than a Serpent’s Tooth’ in Keep It Crisp 140: Get in the groove, fatso.
1953		R. Chandler Long Good-Bye 123: Out of the way, fatso.
1965		L. Bruce How to Talk Dirty 145: You were sick, weren’t you, fatso?
1975		D. Goines Inner City Hoodlum 135: You little black fatso ... you’re dead, boy!
1980		M. Thelwell Harder They Come 257: If it’s a killing you want Fatso, it’s a killing you get.
1999		K. Sampson Powder 350: Ah, shut it, fatso!
2004		W. Whichelow Notso Fatso 1: Ahoy, there, Fatso!
2024		C. Stella Joey Piss Pot 180: ‘Hey, fatso, I’m here to talk sense into you’.

2. a fat person; thus a nickname.

1935		Archie Seale Man About Harlem 23 Nov. [synd. col.] ‘Fatso’ Graham and Marion Johnson [...] are sizzling so hot.
1943		R.L. Bellem ‘Phoney Shakedown’ Dan Turner - Hollywood Detective Feb. 🌐 I thought it was Fatso Venner who drilled her on that forecourt.
1951		P. Whelton Angels are Painted Fair 45: Not that I think Mr. Fatso would leave the office alone.
1952		J. Jones From Here to Eternity (1998) 615: If Fatso tells you to eat a plate of shit, you eat it, and whats more, you like it, hear?
1960		E. De Roo Big Rumble 113: ‘You shoulda kissed her goodnight,’ Larry told him. ‘Yeah. Let Fatso White do it,’ Donald snarled.
1979		‘Iceberg Slim’ Airtight Willie and Me 12: Willie walked, with head down, toward a florid fatso.
1987		‘Joe Bob Briggs’ Joe Bob Goes to the Drive-In 80: Another one is this fatso named David, who has a lot of money.
1998		L. Stringer Grand Central Winter (1999) 37: Fatso waddles up to our cell, asks a question.
2005		J. Stahl I, Fatty 115: The perpetual happy-go-lucky fatso funster.
2019		Star Gaz. (Elmira, NY) 27 Feb. 10B/4: I heard Glen beck call film-maker Michael Moore a ‘fatty-fatty fatso’.
2020		(con. 1991-94) W. Boyle City of Margins 93: This wasn’t fatsos drinkng beer and goofing off.