Iustus

iustus is a Latin adjective meaning just, lawful, or righteous. In classical Latin it denotes conformity to law or moral rightness and can describe people, actions, or qualities. It is declined as a second-declension adjective, with masculine nominative singular iustus, feminine iusta, neuter ius­tum; and with corresponding forms across cases and numbers (e.g., iustus, iusti, iusto, iustum; iusta, iustae, iusta, iustam; iustum, iusti, iusto, iustum; plural iusti, iustae, iusta; iustorum, iustarum, iustorum; iis etc.).

Etymologically, iustus derives from ius, meaning law or right, with the adjectival suffix -tus, yielding the sense “lawful, rightful, just.” The word has given rise to related terms in many Romance languages, such as Spanish justo, Italian giusto, French juste, and Portuguese justo, all of which descend from the same Latin root.

Usage and significance: in classical authors, iustus appears in moral and legal contexts to describe rightful conduct or legitimate status. In religious Latin, the word is frequently used in translations of Greek dikaios, conveying the sense of righteousness or godliness. It also contributes to abstract nouns such as iustitia (justice) and iustificatio (justification).

In modern reference works, iustus is noted for its broad semantic range—from ordinary legality to moral virtue—reflecting the Latin tradition’s linkage of law, equity, and virtue. The term also survived as a given name in Latin and medieval Christian contexts, with the form Justus appearing in later history.