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Definition 2024

(chiefly US, idiomatic) To know something, even if only a little, about.
- 1881, "Notes of the Fine Arts," New York Times, 7 Feb., p. 3 (retrieved 22 Sep. 2009):
  But the great artist doesn't know "beans" about driving oxen. He has put his driver on the "off" side of the yoke.
- 1963, "Dear Ann Landers," Pittsburgh Post-Gazette, 12 Mar., p. 17 (retrieved 22 Sep. 2009):
  If this self-styled expert in the field of human relations knew beans about handling people he'd get more work out of the women and fewer tears.
- 2008, Charles Paikert, "Ken Fisher," InvestmentNews, 14 Jul. (retrieved 22 Sep. 2009):
  If wealth managers actually knew beans about anything, they would be in asset management.
(chiefly US, idiomatic) To know nothing, or almost nothing, about.
- 1986, "Editorial: The Cabinet Races," Gainesville Sun, 22 Aug., p. 18A (retrieved 22 Sep. 2009):
  His primary opponent, Raphael Herman, is a real estate salesman who frankly admits he knows beans about insurance.

Often used in grammatical constructions containing a negative, as for example "He doesn't know beans about it."
Also simply "know beans", to know anything at all.

to know nothing, or almost nothing, about