Today’s English Grammar rule discusses the words REGARDLESS and IRREGARDLESS.
REGARDLESS mean NOT to regard or consider something, the meaning given by the suffix LESS, so this term is considered a negative. The prefix IR also causes a word to become a negative, so when combined with the suffix LESS, one creates a double negative in one word. In other words, IRREGARDLESS makes no sense and is improper. Do not use the term IRREGARDLESS; instead, use REGARDLESS.