[med. L. phrase, lit. ‘from what is done afterwards’ (ex from, out of, postfacto, abl. of postfactum, neut. pa. pple. of *postfacĕre, f. post after + facĕre to do). The separation of postfacto in current spelling is erroneous.] From an after act or deed; = ‘after the fact.’
1649. Bp. Hall, Cases Consc., I. x. 89. To buy those goods wch you know … to be stoln … for what doe you else herein, but ex-post-facto partake with that there, who stole them?
b. quasi-adj. Done after another thing, and operating retrospectively, esp. in Ex post facto law.
1789. Bentham, Princ. Legisl., xv. § 3. Cases in which punishment must be inefficacious … Such are the cases of an ex-post facto law.
1798. R. Cumberland, trans. Aristoph., Clouds, in Observ., VI. 240. May not I Take up the cause of youth … Remitting and consigning to oblivion All ex-post-facto beating?
1823. Lingard, Hist. Eng., VI. 486. By an ex post facto law, those who had taken the first oath against the papal authority, were reputed to have taken … a second and much more comprehensive oath, which was afterwards enacted.
1845. McCulloch, Taxation, II. vi. § 2. They might have objected to the tax had it been ex post facto.
