Late 15th century; earliest use found in Rolls of Parliament. From Anglo-Norman premunition (in law) prior notification, forewarning and Middle French premunition, French prémunition preparation, provision, precautionary action, state of relative immunity to severe or symptomatic infection by a pathogen resulting from the continued presence of small numbers of the same pathogen in the body and its etymon classical Latin praemūnītiōn-, praemūnītiō strengthening of a case in advance to forestall objections, in post-classical Latin also advance fortification (Vetus Latina), forewarning, advance notice from praemūnīt-, past participial stem of praemūnīre to fortify, in post-classical Latin also to forewarn + -iō.