Irregardless is a hot-button word among grammarians, and that makes it confusing for writers. Is it a word, or isn't it? Should you be using it in your writing, or shouldn't you? It all depends on where you stand on this debate. Many wordsmiths either totally love it, or completely hate it.
If you look up irregardless in the dictionary, you're going to find it. The Oxford English Dictionary and the American Heritage Dictionary both have a listing for this word, which would seem to legitimize it. However, in both cases the word is listed as "nonstandard," and the Heritage actually defines the word as regardless.
Doesn't that mean irregardless isn't a word? That all depends on how you view it. Because the word has been accepted into the dictionary and because it has found its way into the common vernacular and because it has a definite meaning (regardless), many passionately argue that irregardless is most certainly a word.
Others feel just as passionately that it's not.
No, It Isn't
If you break it down, irregardless just stops making sense. The ir prefix is negative in nature, but then so is the less suffix. Therefore, in the word irregardless you're actually saying something that more literally translates into without without regard. By itself, regardless already means without regard, and the extra prefix only emphasizes the negative...nonsensically.
As any writer knows, double negatives just aren't allowed.
Irregardless is recognized in the dictionaries that set the standard for language as non-standard words, but the harshest definitions for the word are offered by Urban Dictionary. Of all wordsmiths, this online collection seems to have the worst opinion of the word. It's defined as being used only by the ignorant, which is a pretty harsh characterization.
So, does irregardless have a place in your writing? What's the rule of bad grammar? Only in dialogue. It's okay, and sometimes quite proper, to use bad grammar or incorrect words if that's true to the way a specific character speaks. But since technically irregardless isn't an actual word (it's more of a slang term), you shouldn't use it in the rest of your narrative.