The doctrine (-ism) pertaining to (*-al*) faith (fiducia) that is inherently heretical (haeresis). This directly encodes the core conflict: the belief is faith, and that very belief is heresy.
The reformer’s radical insistence that salvation required no sacraments, no works, and no institutional mediation was swiftly condemned as haeresiofiducialism—a dangerous doctrine that reduced religion to bare belief, undermining centuries of orthodox tradition
by sarlinger June 20, 2025