At any rate, I was relieved to see that CMOS is holding the line on “irregardless” after a reader cited this from Wikipedia:
The term “irregardless” has begun to move towards acceptance because incorrect words or grammatical conventions are absorbed by the English language based on common usage.
(I shouldn’t have been surprised to learn that there is a Wikipedia entry for this word, but I was.)
To its credit, Wikipedia includes this admonition:
It is apparent that the word originated from regional deviations and was subsequently re-introduced to the wider English-speaking community, and thus the use of the term should be avoided if one takes the position that this word should not enter common use.
But the CMOS answer lady is more blunt.
At the moment, . . . there’s no reason to change a perfectly good word like “regardless” to one that is bound to raise the hackles of many readers.
Dear readers, here’s hoping your hackles remain prone for the foreseeable future.