n. Lack of regularity; the state of being irregular; deviation from rule, method, order, course, uniformity, etc.; hence, impropriety; disorder; laxity: as, irregularity of proceedings; the irregularity of a curve; irregularity of life or conduct.n. That which is irregular or out of due course; a part exhibiting divergence from the rest; hence, aberrant or immoral action or conduct: as, an irregularity on a surface; to be guilty of irregularities.n. In law, an act or proceeding not wholly beyond the power of the court or party, but done in a manner not warranted by the law or the state of the cause.n. In botany, want of uniformity in size, shape, or measure of union among the members of the same floral circle.n. Eccles., in the Roman Catholic Church, infraction of the rules governing admission to the clerical office and discharge of its functions; a canonical impediment to reception of orders, exercise of clerical functions, or advancement in the church.