† ˈlibertismObs.rare. [app.f. liberty + -ism.] = libertinism 1. 1644Milton Judgm. BucerWks. 1851 IV. 304 A Writ of Error, not of Libertism.1681Ess. Peace & Truth Ch. 33 To avoid both the confusion of Libertism, and the Tyranny of pretended Ecclesiastical Infallibility.