Green’s Dictionary of Slang

(US) a red-headed person; thus attrib.

1839		Westmorland Gaz. 6 July 4/1: A lock of hair in either eye, tangled, sorrel-top whiskers.
1842		Flash (NY) 23 June n.p.: If that red-headed sap [...] didn’t lose half his hair when Melinda Hoag whipped him [...] You had better pay her that quarter, old Sorrel.
1843		Gleaner (Manchester, NH) 1 Apr. n.p.: Lowell Wants to Know [...] What young sorrell top done with that letter that she so slyly slipped into her bosom.
1853		Life in Boston & N.Y. (Boston, MA) 8 Oct. n.p.: We would much rather Old Sorrel Top had gone farther.
1863		‘Edmund Kirke’ My Southern Friends 58: ‘Har, you lousy sorrel-top,’ said the trader to the red-faced and red-headed bar tender [DA].
1864		A.F. Hill Our Boys 239: Oh, no, old sorrel-top, you wouldn’t do that.
1909		‘O. Henry’ Roads of Destiny 298: They don’t raise 74-inch sorrel-tops with romping ways down in his precinct.
1912		Van Loan ‘A Rain Check’ in Ten-Thousand-Dollar Arm 309: That sorrel-top has got half these big leaguers cheated!
1920		Ade Hand-made Fables 217: The Editor wanted to give ‘Red’ a fair Shake, but what was there to say about a Sorrel-Top.
1935		E. Pound letter 17 Apr. in Paige (1971) 273: Redhead [...] carrot-top, sorrel-top, reddy.