Homo homini lupus

Homo homini lupus, or in its unabridged form Homo hominis lupus est, is a Latin proverb meaning "A man is a wolf to another man," or more tersely "Man is wolf to man." It has meaning in reference to situations where people are known to have behaved in a way comparably in nature to a wolf. The wolf as a creature is thought, in this example, to have qualities of being predatory, cruel, inhuman i.e. more like an animal than civilized.

A variation of the proverb appeared as line 495 in the play Asinaria by Plautus: "Lupus est homo homini, non homo, quom qualis sit non novit," which as "Man is no man, but a wolf, to a stranger," or more precisely "A man is a wolf rather than a man to another man, when he hasn't yet found out what he's like."

As a counterpoint, Seneca the Younger wrote, in his Epistulae morales ad Lucilium (specifically, Epistula XCV, paragraph 33), "homo, sacra res homini," which as "man, an object of reverence in the eyes of man."

Erasmus included the proverb in his Adagia, writing of the variation by Plautus, "Here we are warned not to trust ourselves to an unknown person, but to beware of him as of a wolf."

The philosopher, theologian, and jurist Francisco de Vitoria (in Latin, Franciscus de Victoria) that the poet Ovid disagreed with the proverb: "'Man,' says Ovid, 'is not a wolf to his fellow man, but a man.'"

Thomas Hobbes drew upon the proverb in his De Cive, "To speak impartially, both sayings are very true; That Man to Man is a kind of God; and that Man to Man is an arrant Wolfe. The first is true, if we compare Citizens amongst themselves; and the second, if we compare Cities." Hobbes was describing the tendency of people to act fairly and generously toward other people in the same society and the tendency of societies to act deceptively and violently toward other societies, or , "In the one, there's some analogie of similitude with the Deity, to wit, Justice and Charity, the twin-sisters of peace: But in the other, Good men must defend themselves by taking to them for a Sanctuary the two daughters of War, Deceipt and Violence."

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