Vincible and invincible ignorance

Vincible ignorance is, in Catholic moral theology, ignorance that a person could remove by applying reasonable diligence in the given set of circumstances. It contrasts with another concept in Catholic moral theology, invincible ignorance, which is an ignorance that a person is either entirely incapable of removing, or could only do so by supererogatory efforts (i.e., efforts above and beyond normal duty).

Source: Wikipedia — Vincible and invincible ignorance (CC BY-SA 4.0)