Green’s Dictionary of Slang

doughboy n.1

also doe-boy, dough
[? the large round buttons worn by Civil War soldiers, reminiscent of the doughnuts or the boiled dumplings, based on flour and rice and known as doughboys, that were a military staple; or f. the dough or pipeclay used to clean US soldiers’ belts in mid-19C; note Mencken, The American Language (3rd edn, 1936): ‘Doughboy is an old English navy term for dumpling. It was formerly applied to the infantry only, and its use is said to have originated in the fact that the infantrymen once pipe-clayed parts of their uniforms, with the result that they became covered with a doughy mass when it rained’]

(orig. US milit.) a US soldier, orig. those serving in the Mexican War c.1847; subseq. replaced by boonie rat n., GI etc.

N. Dana Monterrey Is Ours! 166: We ‘doughboys’ had to wait for the artillery to get their carriages over.
[US] in R.G. Carter Four Brothers in Blue (1978) 19 Sept. 119: We do the fighting and leave dead cavalrymen for the ‘dough boys’ to pick up.
[[UK]J. Keane On Blue Water 36: These ‘'water whelps,’ as we called them, are properly called ‘dough-boys,’ but our ‘grub-spoiler’ — pet name for ship’s cook — called them ‘swimmers,’ probably because they were such heavy sinkers].
[US]E. Custer Tenting on the Plains (rev. edn 1895) 230: Hullo, there! joined the doe-boys, eh? How do you like hoofing it? [Ibid.] 516: A ‘doughboy’ is a small, round doughnut served to sailors on shipboard, generally with hash. Early in the Civil War the term was applied to the large globular brass buttons on the infantry uniform, from which it passed, by a natural transition, to the infantrymen themselves.
[US]K. Munroe Forward, March 21: That is a term common to ‘doughboys’.
[US]C. M’Govern ‘Soldier Sl.’ in Sarjint Larry an’ Frinds n.p.: doughboys:—Infantrymen.
L.N. Smith Lingo of No Man’s Land 29: DOUGHBOY An infantryman, so called because infantry- men once rubbed their uniforms with pipe clay, and in the rain the clay made dough.
[US]H.C. Witwer Smile A Minute 14: He claims I have got to forget all about whatever friends I got in the company amongst the doughboys whilst on duty.
[US](con. 1918) L. Nason Chevrons 205: They [...] found themselves confronted by half a dozen unshaven doughboys with fixed bayonets.
[US](con. 1919) Dos Passos Nineteen Nineteen in USA (1966) 535: The heaving airless corridor of seasick seascared doughboys.
[US]J. Archibald ‘Crash on Delivery’ in Flying Aces Nov. [Internet] The doughs who stumbled over this treasure left the Heinie paymaster where they found him.
[US]J. Archibald ‘Meat Bawl’ in Popular Detective Aug. [Internet] Three emaciated doughs sitting in a slit trench without food or water.
[US]J.M. Cain Moth (1950) 343: He figured they might not like it to see her picture on every doughboy’s shoulder.
[US](con. 1945) F. Davis Spearhead 61: Tell the doughs to hook up with third platoon.
[US]W. Burroughs Naked Lunch (1968) 82: A G.I. or a Doughboy or the unknown Soldier.
[US]M. Braly False Starts 42: The tunic was the style worn by the doughboy.
[US]W. Diehl Hooligans (2003) 424: What happened out there, doughboy?
[US]Randolph & Legman Ozark Folksongs and Folklore I 576: Under the erroneous notion that the American doughboys of World War I might want to sing Civil War ‘minstrel’ or music hall bawdy songs.
[US]J. Stahl Pain Killers 132: Bad as the Doughboy-era dope had made me feel, I already missed it.
[US](con. 1954) ‘Jack Tunney’ Tomato Can Comeback [ebook] Run away while you can, doughboy — justlike you did at Chosin.