The role of religious vocabulary in the political theorisation in the 14th century originates in the conflict between pope and king. In this period, under the influence of Charles V (1364 - 1380), several political philosophical works were translated into French for the first time such as City of God by the saint Augustine and Jean de Salisbury's Policraticus. In this article the author sets out to analyse semantic neologisms which appear in these texts. Why and how do the translators choose to use a word that already exists in the language and how doe semantic transfers come about? Lexical context as well as syntax are then used in order to understand the use (and necessity) of new meanings of existing forms. Thus religious vocabulary extends its authority into the field of political science. The analysis in this article is based on the group corrompre/corruption in these two 14th century translations.