Envy, invidia, is sorrow at another's good, and it is the vice the tradition treats as most purely spiritual and most nearly diabolical, since it takes no pleasure of its own but only pain at someone else's. Gregory the Great added it to the list Evagrius had drawn up, and Aquinas classes it as a capital vice and as a sin against charity, distinguishing it carefully from emulation, which desires the good one sees in another, and from indignation at undeserved good, neither of which is envy. Dante places the envious in Purgatorio with their eyelids sewn shut with wire, because in life they could not bear to see. The virtue set against it in the popular scheme is kindness or charitable goodwill, sometimes given as gratitude: rejoicing in the good of another rather than grieving at it.
The tension between pride and envy as the more fundamental sin was itself debated: Augustine held pride the root of all sin generally, in the City of God, while the Wisdom text's naming of envy as the devil's own gateway sin led some medieval theologians to treat envy as pride's most direct expression against another rather than a wholly separate root. Aristotle had already drawn a version of this distinction long before Aquinas: in the Rhetoric he defines phthonos, envy, as pain at another's good simply because it is theirs, and sets against it nemesis, pain at good fortune that is genuinely undeserved, treating the second as the reasonable response the tradition's own distinction between envy and indignation still echoes.