I think trying to define clear, one word names for Fighter, Rogue, Cleric, and Wizard are just doomed to failure. With the exception of Fighter, which has remained remarkably the same since 1e (save for the new inclusion of warlord ideals from 4), the others have branched out, redefined themselves in a lot of ways, back and forth. We have combinations, divides of, and lots of random permutations. I've heard some call bard a mix of rogue and cleric, and warlock an arcane rogue.
But, in the end, it keeps coming back to Fighter, Rogue, Cleric, Wizard.
Even the power sources in 4e kinda repeated themselves for a second time on those four roles. Martial characters had secondary striker traits. Arcane characters all had Controller elements about them. Divine classes all had Leader abilities. Primal were all secondary Defender bits. Funny how that worked out. All the arcane classes had a bit of wizard artillery in them, all the divine had buffing, all the martials heavy on the offensive single target damage. 4e virtually ended up as a 4x4 grid of the four core classes mixing. Well, 4x5 with psionics doing weird things with their power points, but that's another matter.
So, yeah. I feel like I should start talking about how the four classes match up to a four elemental ensemble (with the GM as the fifth element of Void!) Earth-fighter, wind-rogue, water-cleric, fire-wizard. Or the Five Man Band. Something.