Green’s Dictionary of Slang

(US) the epitome, the ‘real thing’ .

1863		Dly Green Mountain Freeman (Montpelier, VT) 6 May 2/2: Just wait until he opens his mouth, and if the plum [i.e. a courted woman] does not prove to be a real persimmon, I shall miss my reckoning.
1885		Springfield Globe-Republic (OH) 26 Feb. 3/4: Mothers and Guardians may read the main epistle [...] the real persimmon is devoured by the daughter when she has the opportunity to soak the stamp loose.
1910		Eve. Statesman (Walla Walla, WA) 19 Feb. 3/6: The Mackintosh, quoted in some books at 100 to 1, was the real persimmon.

to succeed, to win, to make a profit; thus n. persimmon raker, a powerful individual.

1872		Schele De Vere Americanisms 50: To rake up the persimmons is a frequent term for ‘pocketing the stakes.’.
1909		Coshocton (OH) Daily Times 27 Aug. 8/7: We’ve grown some, but I don’t see that we’re knocking any particularly Big Persimmons.
1910		Morn. Appeal (Carson City, NV) 28 Aug. 3/3: There is the man [...] voted as the boss [...] but the fellow behind the scenes is the real persimmon raker.

(US) someone or something excellent, admirable.

1849		N.Y. Daily Globe 6 Apr. 2/4–5: [As Kate Hastings] figured largely at the late Taylor Inauguration Ball in Washington, we are led to conclude that she must be some persimmons.
1905		St Louis Republican (MO) 23 July 6/6: No siree. Dat she ain’t. She’s some persimmons as de head of de house herself.
1921		Jackson Co. Sentinel (TN) 17 Mar. 1/1: I make him feel that he is some persimmons [...] I speak words to tickle his vanity.

(US) that’s fine, that’s satisfactory.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1906		S. Ford Shorty McCabe 127: Whoope-e-e, me fellers! You’re the real persimmons, you are.

see that ain’t hay under hay n.