adj. & n.
--adj.
1. not regular; unsymmetrical, uneven; varying in form.
2 (of a surface) uneven.
3 contrary to a rule, moral principle, or custom; abnormal.
4 uneven in duration, order, etc.
5 (of troops) not belonging to the regular army.
6 Gram. (of a verb, noun, etc.) not inflected according to the usual rules.
7 disorderly.
8 (of a flower) having unequal petals etc.
--n. (in pl.) irregular troops.
Derivatives:
irregularity n. (pl. -ies). irregularly adv.
Etymology: ME f. OF irreguler f. LL irregularis (as IN-(1), REGULAR)