primogenitive adjective 2noun 1forms 2 adjective2 •Firstborn.This left Henry de Bourbon, the Huguenot King of Navarre, as the primogenitive heir to the French throne, an eventuality the Catholic League in France was unwilling to accept. — 2014 •Based on or pertaining to primogeniture.The system of primogenitive inheritance utterly destroys this salutary principle ; and for the following reasons: — 1834 noun1 •(no longer used) primogeniture formsmore primogenitive · most primogenitive