irregular
B2Adjektiv/US /ˌɪrˈɛɡjəlɚ/ ĭr-ĔGY-əl-ər; UK /ˌɪrˈɛɡjəlɚ/ ĭr-ĔGY-əl-ər/
Not regular; not conforming to a law, method, or usage recognized as the general rule; not according to common form; not conformable to nature, to the rules of moral rectitude, or to established principles; not normal; unnatural; immethodical; unsymmetric
