Green’s Dictionary of Slang

1. small, undersized.

[1683		Fifteen Real Comforts of Matrimony 45: But what may we think of those decrepit half-pint Lechers […] as sapless as a dry’d Fennel-stalk].
[1707		N. Ward Compleat and Humorous Account of Remarkable Clubs (1756) 16: They dwindled from an eminent Club of Experimental Philosophers, into a little Cinacal Cabal of Half-pint Moralists].
1900		Bulletin (Sydney) 26 May 31/1: [T]hese hundreds of men stood quietly by whilst a stupid push of half-pint larrikins, numbering not more than a score, utterly demoralised the meeting.
1926		Judge (NY) 91 July-Dec. 31: Half-pint - Shrimp, small, undersized.
1932		E.C. Segar ‘Popeye’ Thimble Theatre series No. 2 n.p.: We ain’t goner mix up in no ‘half-pint’ wars.
1933		J.T. Farrell Gas-House McGinty 55: That half pint p--k ain’t no brother of mine.
1935		Z.N. Hurston Mules and Men (1995) 26: All he ever got called was on some saw-mill, half-pint church or some turpentine still.
1943		D. Burley N.Y. Amsterdam Star-News 3 Apr. 13: Shavers, the half-pint swing merchant.
1954		C. Chessman Cell 2455 65: He’s not just a half-pint show-off.
1959		(con. WWII) B. Cochrell Barren Beaches of Hell 38: I don’t take that from no half-pint pogey.
1995		R. Campbell Wizard of La-La Land (1999) 161: A half-pint microwave probably used for nothing more than TV dinners.

2. (US) of a child, short; thus quarter-pint, even smaller.

1935		J. Conroy World to Win 117: Little half-pint runt, like an owl.
1939		P. Di Donato Christ in Concrete 127: He was the half-pint jerk-off, he was godson, he was the titty-drinker.
1949		N. Algren Man with the Golden Arm 294: A half-pint Negro girl came skipping down the alley hauling a quarter-pint one by the hand.