a. [ L. irrationalis: cf. F. irrationnel. See In- not, and Rational. ] [ 1913 Webster ]
It seemed utterly irrational any longer to maintain it. I. Taylor. [ 1913 Webster ]
n. The quality or state of being irrational; absence of rationality. “Brutish irrationaliity.” South. [ 1913 Webster ]
adv. In an irrational manner. Boyle. [ 1913 Webster ]
n. Irrationality. [ 1913 Webster ]