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. irregularity n. (pl. -ies). irregularly adv.
[ ME f. OF irreguler f. LL irregularis (as IN-(1), REGULAR) ]