Supposably…
First things first. As soon as I typed “irregardless” into a Microsoft Word file, a red squiggle of death appeared. You know the type. That alone should give you pause, though the Editor/Spell Check tool is admittedly problematic.
Let’s break this conundrum into bite-size pieces:
Irregardless has a prefix (ir), a main root (regard),* and a suffix (less).
“Ir” is a variant of “il,” “im,” and “in,” all meaning “not.” Why so many options for the same thing? That’s simply based on the etymology of the root word and its spelling — “im” is used before words beginning with “b,” “m,” and “p,” for example, and “ir” is used before words beginning with “r.”**
“Regard” in this form is an adverb, which is a word that modifies or clarifies the meaning of a verb, adjective, or another adverb.
“Less” is a suffix meaning “without” or “not having.”
So the prefix and suffix mean the same thing. This is essentially a double negative, which is why I didn’t even bother to define “regard” above. Because if you know the meaning of “regardless,” you know the intended meaning of “irregardless,” despite its nonsensical construction. If you right-click on the red squiggle of death, it will prompt you with the replacement “regardless.” If you text “irregardless,” autocorrect will more than likely change it to “regardless.” In fact, if you search “irregardless” in Merriam Webster, the listed definition is — you guessed it — “regardless.”
So why is “irregardless” in the dictionary, if not as a testament to its veracity as a legitimate word? Because Merriam Webster is as much responsible for reporting information based on usage as it is for the judicious treatment of those words. People persist in using “irregardless,” and Merriam Webster has magnanimously declared the word “nonstandard.”
Our take is a little less generous.