(Latin: rigere, to be stiff)
The moral teaching which holds that when there is a conflict of two opinions, one in favor of the law, the other in favor of liberty, the law must always be observed, even if the opinion in favor of liberty is the more probable or very probable one as compared with its opposite.
Rigoristic writers and teachers have appeared in all ages.
It was especially in the 17th century, however, that a regular system of rigorism was proposed and defended by certain leaders, particularly the Jansenists.
The doctrine has done great mischief.
A large number of persons remained away from the Sacraments, especially in France, during the 17th and 18th centuries, or received them but seldom, under pretext of being too unworthy.
Absolute rigorism (or tutiorism, the safer course) was condemned by Pope Alexander VIII on 7 December 1690.
New Catholic Dictionary