Primogenitary, meaning "relating to the first-born child" or "inheriting through the first-born child," has a handful of synonyms that convey similar meanings. Firstly, there's "primogenital," which refers to something originating from the first-born or earliest state, while "primogenitive" pertains to the first-born's right to inherit. "Primordial" and "original" also convey a sense of being first or earliest in existence, while "progenital" and "progenitive" relate to the production or ancestor of an individual or family. Additionally, "patrilineal" and "agnate" refer to inheritance through the father's line, often associated with primogeniture in certain cultures and societies.