irregardless

 
Pronunciation: /ˌɪrɪˈgɑːdlɪs/

adjective & adverb

informal
  • regardless: the photographer always says, irregardless of how his subjects are feeling, ‘Smile!’

Origin:

mid 19th century: probably a blend of irrespective and regardless

Irregardless means the same as regardless, but the negative prefix ir- merely duplicates the suffix -less, and is unnecessary. The word dates back to the 19th century, but is regarded as incorrect in standard English.