The practice and beliefs of Nicodemites; specifically the view held by certain 16th-cent. Protestants during the Counter-Reformation that outward conformity with the Catholic state was acceptable if one's true faith continued to be inwardly professed.
1950s. From the name of Nicodemus + -ism. Jung attributes the term (as Middle French Nicodemisme) to Calvin, although Calvin's Excuse, de Jehan Calvin, a Messieurs les Nicodemites only has the related terms Nicodeme, Nicodemiser, and Nicodemite.