illegitimus

Illegitimus is a Latin adjective meaning not legitimate, unlawful, or not officially sanctioned. It is built from the prefix in- (a negating form) combined with legitimus, meaning lawful or legitimate. The word follows standard Latin adjective decline, with masculine form illegitimus, feminine illegitima, and neuter illegitimum.

In classical Latin, illegitimus often described people born outside of wedlock, as in fili(us) illegitimus, denoting an illegitimate child. The term also applied more broadly to actions, claims, or instruments considered unauthorized or invalid, depending on context.

Roman law and social practice treated illegitimacy as a condition with potential legal and social consequences. Legitimate status could influence inheritance, parental rights, and social standing, though the exact effects varied over time and by jurisdiction. Over the centuries, many legal systems evolved away from rigid distinctions of legitimacy, integrating paternity recognition, adoption, and civil reforms that mitigated or removed former disadvantages.

Legacy and descendants: Illegitimus is the etymon of numerous modern terms in Romance languages and in English. English uses illegitimate, while Romance languages preserve forms such as ilegítimo (Spanish, Portuguese), illegittimo (Italian), illégitime (French), and ilegítimo in other languages. In modern usage, illegitimacy is generally discussed as a historical or legal concept, with contemporary systems increasingly focusing on individual rights and parentage recognition rather than status by birth alone. In ecclesiastical or scholarly Latin, illega­litimus is less common, with more explicit phrasing often preferred.