arrhythmic Syllabification: (ar·rhyth·mic)Pronunciation: /əˈriT͟Hmik/ (also arhythmic)Definition of arrhythmic adjective not rhythmic; without rhythm or regularity:the arrhythmic clip-clop of pony steps Medicine of, relating to, or suffering from cardiac arrhythmia. Derivatives arrhythmical adjective arrhythmicallyPronunciation: /-mik(ə)lē/ adverb arrhythmic in other Oxford dictionaries Definition of arrhythmic in the British & World English dictionary