Source : Webster's Revised Unabridged Dictionary (1913)

Irregularly \Ir*reg"u*lar*ly\, adv.
   In an irregular manner.

Source : WordNet®

irregularly
     adv 1: in an irregular manner; "the patient is breathing
            irregularly" [ant: {regularly}]
     2: having an irregular form; "irregularly shaped solids" [ant:
        {regularly}]
     3: in an irregular manner; "her letters arrived irregularly"
        [syn: {on an irregular basis}] [ant: {regularly}]
     4: in an irregular manner; "the stomach mucosa was irregularly
        blackened"