Moral obligation
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
A duty which is valid and binding in the forum of the conscience but is not recognized by the law as adequate to set in motion the machinery of justice; that is, one which rests upon ethical consideration's alone, and is not imposed or enforced by positive law.
Taylor v. Hotchkiss, 81 App. Div. 470, 80 N. Y. Supp. 1042; Goulding v. Davidson, 25 How. Prac. (N. Y.) 483; Bailey v. Philadelphia, 167 Pa. 569, 31 Ail. 925, 46 Am. St. Rep. 691.