Irregardless. I often get uneasy whenever I hear this word. The word “irregardless” is redundant. The negative prefix “ir” and the negative suffix “less” makes it a “double negative.”

The American Heritage Dictionary of the English Language Fourth Edition reads:

Irregardless is a word that many mistakenly believe to be correct usage in formal style, when in fact it is used chiefly in nonstandard speech or casual writing. Coined in the United States in the early 20th century, it has met with a blizzard of condemnation for being an improper yoking of irrespective and regardless and for the logical absurdity of combining the negative ir– prefix and –less suffix in a single term. Although one might reasonably argue that it is no different from words with redundant affixes like debone and unravel, it has been considered a blunder for decades and will probably continue to be so.