Irregardless is a word that people love to hate. In fact, many would say that it isn’t a word at all, but rather the hideous result of a collision between irrespective and regardless. Here’s the Oxford Dictionary of English on irregardless:
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.
And here’s Merriam-Webster with the American perspective:
Irregardless originated in dialectical American speech in the early 20th century. Its fairly widespread use in speech called it to the attention of usage commentators as early as 1927. The most frequently repeated remark about it is that “there is no such word.” There is such a word, however. It is still used primarily in speech, although it can be found from time to time in edited prose. Its reputation has not risen over the years, and it is still a long way from general acceptance. Use regardless instead.
The Chicago Manual of Style, in its Word Usage section, gets straight to the point:
irregardless. An error. Use regardless (or possibly irrespective).
Finally, the New Oxford Dictionary for Writers and Editors makes Chicago‘s ruling look positively verbose:
irregardless use regardless
So what does all of this mean? Essentially, it means that irregardless, through years of service, has become acknowledged as a Real Word. You can use it for Scrabble.
Before you use it anywhere else, however, you should think about the effect it will have on your reader. Irregardless isn’t a properly constructed word; as explained in the Oxford quote above, the ir- duplicates the -less, and is redundant. If you want to say that something is happening “without regard”, there’s already a word that does exactly that: he greeted all his guests with a broad smile, regardless of their politics. To use an incorrectly constructed word, when there’s a better one that does exactly the same job, is bad writing.
What’s more, even though it means the same thing as regardless, you can’t just drop it into a sentence as an exact synonym for the other word, because it brings with it all the weight of this controversy. As such, it would draw the reader’s eye; they would wonder why you’re using the less acceptable word. If the reader doesn’t approve of the word—and many won’t—you risk alienating them, and you would certainly distract them from the real subject of your writing.
The only time when it might be appropriate to use irregardless is when you want to achieve a particular effect. For example, it might work well in the direct speech of an uneducated character, especially if you want to contrast them with another who chooses his words more carefully. In this case, you should make it clear that it’s the character’s error, and not your own.
