Contemplate this, dude: that when I call you dude, there’s a whole range of things I might mean—you’ll understand me from my intonation and the overall context—but each time, I’m also reinforcing a specific kind of social relationship. No matter how I use the word, it always implies the same thing: solidarity without intimacy. It says close, but dude, not too close.
What’s up with that?
Dude may be the most Mandarin Chinese word in American English. In Mandarin, depending on how I intone the single syllable ma, I could be saying “mother” (mā), or I could be saying something as radically distinct as “horse” (mă).
Dude has a comparable quality. Just think of the last time you did something awesome in the presence of a friend who affirmed your awesomeness with the exclamation Duuude! Or the last time you said something objectionable to someone who began setting you straight with a firm and sober Dude. There may not be any obvious difference in denotation between these cases, but the difference in connotation is, you’ll appreciate from experience, pretty major.
So what does the word itself mean? I can tell you what a mother is, and I can tell you what a horse is. But what’s a dude?
Dictionaries struggle with this question. Here, for instance, is Merriam-Webster:
1: a man extremely fastidious in dress and manner: DANDY
2: a city dweller unfamiliar with life on the range; especially: an Easterner in the West
3: FELLOW, GUY—sometimes used informally as a term of address <hey, dude, what’s up>
Seriously, dudes? […]
(from The Atlantic, J. J. Gould, 23.10.2013)