What is Action On The Case?

Legal Definition
A species of personal action of very extensive application, otherwise called "trespass on the case," or simply "case," from the circumstance of the plaintiff's whole case or cause of complaint being set forth at length in the original writ by which formerly it was always commenced. 3 Bl. Comm. 122. Mobile L. Ins. Co. v. Randall, 74 Ala. 170; Cramer v. Fry (C. Ct) 68 Fed. 201; Sharp v. Curtiss, 15 Conn. 526; Wallace V. Wilmington & N. R. Co., 8 Houst (Del.) 529, 18 Atl. 818.
-- Black's Law Dictionary
Legal Definition
A common-law remedy for injury consequentially resulting to the person, property or reputation, from the commission of a tort, in cases where trespass will not lie. Same as “Trespass on the Case,” and “Case.” See 18 Johns. (N. Y.) 257, 9 Am. Dec. 210.
-- Ballentine's Law Dictionary