Section — Wouters, Manual of Moral Theology
Scholion. On Imperfections
I. Notion. Imperfection is sometimes taken for a wholly involuntary transgression of a precept, such as involuntary distractions during prayer, involuntary excesses in indignation, jesting, laughter, etc. Now although these things do not contain sin, nor can all of them be avoided, nevertheless let us strive to lessen them.
Imperfection by force of the word is the absence of some perfection. It is distinguished as negative and positive. Negative imperfection is the mere absence of perfection; positive imperfection, which is also called privation, is the absence or lack of a perfection which it is fitting should be present in someone, and it is had when someone deliberately chooses the less perfect, according to what was said in n. 213.