Entry 1 sense Webster, 1913 Abnormal /ăb-nôr'-məl/ · Ab·nor·mal · IPA /ˌæbˈnɔɹ.ml̩/ 01 a. Not conformed to rule or system; deviating from the type; anomalous; irregular. 1. Not conformed to rule or system; deviating from the type; anomalous; irregular.