A colleague approached the Word Nerd to ask about the differences between regardless and irregardless. Simply put, irregardless is not recognized as a word by many dictionaries (including the Word Nerd’s dictionary of choice the Canadian Oxford). However, dictionary.com lists irregardless as a “non-standard” word that can be used for emphasis. Unless you happen to have a PhD in English grammar and are known for your word nerdish ways, I would not recommend using irregardless as many people consider the use of this word to be a mark of ignorance.
Irregardless contains a double negative – “ir” and “less” – which renders its meaning hard to understand. Regardless (an adjective) means “without consideration.” For example: Regardless of the cost, we are going to take the kids to Disneyland next year.