irregardless |ˌiriˈgärdlis| adjective & adverb informal regardless. ORIGIN early 20th cent.: probably a blend of irrespective and regardless .USAGE Irregardless, with its illogical negative prefix, is widely heard, perhaps arising under the influence of such perfectly correct forms as: irrespective. Irregardless is avoided by careful users of English. Use regardless to mean 'without regard or consideration for' or 'nevertheless': | I go walking every day regardless of season or weather.