irascible

Easily provoked to outbursts of anger; irritable.

The divine Plato, whose doctrines are not sufficiently attended to by philosophers of the present age, allows to every man three souls—one, immortal and rational, seated in the brain, that it may overlook and regulate the body—a second consisting of the surly and irascible passions, which like belligerent powers lie encamped around the heart[…]

Like some poor devils ashore that happen to know an irascible great man, they make distant unobtrusive salutations to him in the street, lest if they pursued the acquaintance further, they might receive a summary thump for their presumption.

Relating to the irascible passions.

The irascible and concupiscible appetites are distinguished by different aspects of their objects. The object of the concupiscible faculty "is sensible good or evil, simply apprehended as such" while good and evil considered as "arduous or difficult … is the object of the irascible faculty."