Chapter I. On Irregularities in General

Irregularity is a perpetual impediment to this, that someone be enrolled among the clergy, or that he receive Orders or exercise those received. Irregularity is alienation from the rule; rule in Greek is called canon; canon formerly meant the catalogue of clerics who were enrolled under some Title (Church) and were called canons; irregulars with us anciently were those alien from the canon.

Irregularity therefore signifies a prohibiting impediment by which someone is prevented from being enrolled among the clergy, warding him off from Order or from its exercise; it signifies a perpetual impediment, namely one which is judged such that it does not cease by the fact itself, but which is removed only by legitimate power. And in this respect perpetuity is to be held as the essential character of irregularity; on the contrary, things which cease naturally by the course of time, by study, etc., are not, nor are they to be held as, irregularities properly so called. Therefore temporal irregularity is excluded. Irregularity derives its origin from defect or from delict, because that impediment, stain-note, arises on account of some defect, for instance, some defect of body, or on account of some delict, for instance apostasy from the faith.

I say. No irregularity is ever incurred unless it is expressed in canon law.

Thus in the new Code it is clearly declared:

No perpetual impediment which comes under the name of irregularity, whether it is from defect or from delict, is contracted, except what shall have been expressed in the canons which follow (Can. 983).

And therefore the things which are named in canons 984, 985 alone come under the name of irregularities. However many other things there may be which by natural or divine law prohibit one from the clergy, unless they are found expressed in the new Code, they are not irregularities.