St. Augustine first applied the pagan title of hero to the Christian martyrs; since then the custom has prevailed of bestowing it not only on martyrs, but on all confessors whose virtues and good works greatly outdistance those of ordinary good people. Benedict XIV, whose chapters on heroic virtue are classical, thus describes heroicity: “In order to be heroic a Christian virtue must enable its owner to perform virtuous actions with uncommon promptitude, ease, and pleasure, from supernatural motives and without human reasoning, with self-abnegation and full control over his natural inclinations.” An heroic virtue, then, is a habit of good conduct that has become a second nature, a new motive power stronger than all corresponding inborn inclinations, capable of rendering easy a series of acts each of which, for the ordinary man, would be beset with very great, if not insurmountable, diffulties (
source).