rationis expers (not gifted with reason): brutus (without the faculty or capacity of perception): mutus (mute, unreasonable, inasmuch as speech implies reason; all three of animals): demens (senseless, and also of things that none but a senseless person would do): insanus (mad, deprived of right reason, insane; of men; then also denoting excess; e.g., moles, montes). An irrational animal or being, bestia (opposed to homo). In an irrational manner; Vid: IRRATIONALLY.