homō hominī lupus

Meaning

1. man is a wolf to man (what wolf is to other animals, man is to another man)

Origins

From homō (“a human being, man”) + hominī (“to man”, dative singular of the same) + lupus (“a wolf”). As is typical of Latin proverbs, the sentence is nominal (lacks the copular est). First attested in Erasmus' Adagia, a variation on the proverb alluded to by Plautus in Lupus est homō hominī, nōn homō, quom quālis sit nōn nōvit ("To a human, a human is not a human but a wolf when he doesn't know what the other one is like"). Compare Erasmus' Hominī nūlla fera perniciōsior quam homō ("No beast is more dangerous to a human than another human").