Mean is one of those words that I knew well would have been around forever, but I looked it up to see about some of the particular uses. And as usual, found a few surprises. =)
As a verb, mean has meant “intend, have in mind” even back in the days of Old English. No surprise there. It shares a root with similar words in Dutch and German and various other languages, perhaps from men, which means “think.” But the unexpected part–the question “Know what I mean?” is only from 1834! Of course, that’s as a conversational question, a saying. I daresay the words were uttered as a particular question before that. Know what I mean? 😉
As an adjective, it began life as “low-quality.” Like “a mean hovel” that the poor dude lived in. But it also carried a meaning, rather related, actually, of “shared by all, common, public.” And presumably if something were shared by all, it wasn’t really high in quality, eh? So “inferior, second-rate” was also a natural progression for the word, and came about in the 14th century.
I knew this definition would be the oldest but, when I looked it up, was more interested in when the most common meaning if mean (meaning of mean–ha . . . ha . . . ha . . .) came into play. It acquired the “stingy, nasty” implication in the 1660s, and was then pretty strong. We Americans had to come along to give it a softer side of “disobliging, pettily offensive,” so that didn’t come about until 1839–again, there’s the surprise!

Have no mean Monday, all! 😉