illegitimate

Illegitimate is an adjective with several related meanings. It can describe something not authorized by law or not sanctioned by established rules or standards. It is also used to refer to a child born to parents who are not married, a usage that reflects historical legal distinctions surrounding inheritance and social status. The term derives from Latin illegitimus, meaning “not legal” or “not rightful,” through Old French illegitime.

In historical legal contexts, illegitimacy was a formal status with specific rights and restrictions, particularly concerning inheritance, succession, and social privileges. Legitimation could sometimes be conferred retroactively through subsequent marriage or court action, but in many periods and places illegitimate children faced unequal treatment. Over the 19th and 20th centuries, many legal systems reformed such distinctions, expanding rights for children born outside marriage and reducing or eliminating formal stigma in official documents. Today, the legal significance of illegitimacy has largely diminished in many jurisdictions, though some laws and records still reflect older terminology.

Contemporary usage tends to treat the term as dated or potentially stigmatizing when referring to people. In neutral descriptions, alternatives such as “nonmarital,” or “born outside marriage” are often preferred. The phrase appears in broader, non-person contexts as well, where it denotes lack of legitimacy or justification—such as an “illegitimate claim” or “illegitimate authority”—indicating that something is unlawful, improper, or not grounded in proper authority, rather than focusing on birth status.