verb/sə kʁwaʁ lə pʁə.mje mu.taʁ.dje dy pap/
to think one is God's gift to the world, to think one is the business, to be full of oneself
Synonyms: se croire sorti de la cuisse de Jupiter, ne pas se prendre pour de la merde, péter plus haut que son cul
Literally, “to believe oneself the pope's chief mustard maker”. From a 17th-century legend with no basis in reality that a 14th-century Avignon pope/antipope appointed his nephew as his official mustard maker, said nephew then bragging everywhere about his status.