Green’s Dictionary of Slang

(orig. US) to abandon a trial because the plaintiff or prosecutor has given up the suit, usu. because there is insufficient hard evidence, a key witness has backed down etc.

1845		J.J. Hooper Adventures of Captain Simon Suggs (1851) 138: I would ‘nol pros.’ the case if I were you, and let this grief-stricken old man go home to his dying children.
[1853		J.G. Baldwin Flush Times of Alabama and Mississippi 120: I’ll enter a nolly prossy q. One hundred dollars and fifty better! Jewhellikens!].
1888		Battle Creek Journal 7 Mar. n.p.: The prosecution stated that it would be impossible to secure a conviction in either case, and he asked that they be nolled [DA].
1895		Chicago Times-Herald 7 Nov. 7/1: Judge Seamon today nolled the indictments against Eugene V. Debs [DA].
1901		Honolulu Republican 28 Aug. 5/4: Ah Sam, selling liquor without a license, was nolle pros’d.
1909		J. Ware Passing Eng. of the Victorian Era 183/1: Nolled (American). Form of nolle prosequi. Used by lawyers.
1913		H.A. Franck Zone Policeman 88 21: ‘Here’s where I get my case nol prossed,’ I found myself whispering.
1929		C. Coe Hooch! 80: The D.A. played the game on that an’ satisfied the papers about nol-prossin’ that bump-off over in the East End?
1931		W.N. Burns One-Way Ride 60: This remarkable verdict convinced the state’s attorney that it would be useless to try Herbert and Oberta, and he nolle prossed the case against them.
1934		Z.N. Hurston Jonah’s Gourd Vine (1995) 84: Dis case ain’t uh goin’ tuh be nol prossed uh nothin’ else.
1946		Mezzrow & Wolfe Really the Blues 49: They didn’t have anything on me, so after a few days my case was nolle prossed and I was sprung.
1959		C. Himes Crazy Kill 143: We’ll get that manslaughter charge nol-prossed [...] You ain’t got a thing to worry about.
1979		E. Torres After Hours 11: I know your honor didn’t want to nol-pros this case nohow.
1990		S. Morgan Homeboy 204: Madera will nolle pros Turner’s case.
1997		Simon & Burns Corner (1998) 257: It couldn’t be stetted or nol-prossed or reduced to some unsupervised probation.