Ernest "M-16" Mateen comes to mind. He certainly looked fearsome, but... Also, "Gentleman" Jim Corbett was a dck.
Always thought this was one of the worst nicknames of all time. It's too long and incredibly boring. He was actually a good fighter but apparently not very creative.
Bernard Hopkins - "The Executioner". His style was completely opposite to what his nickname would expect him to fight like. Meldrick Taylor, Tony Tubbs & Tony Tucker - "TNT". None of them were big punchers. Pauline Mallinaggi - "Magic Man". Nothing spectacular about him.
That’s right on the money Greg. “Mysterious” was quite the euphemism, wasn’t it? Applying it to the more modern era, we could say that Andrew Golota moved in “mysterious” ways also.
It's a crying shame the "logic" of assigning Mysterious Billy Smith's nickname didn't continue in to future eras. I feel just certain that Enigmatic Fritzie Zivic and Inscrutable Mike Tyson, would have really caught on.
And wasn’t Darth ‘Vander your classic riddle wrapped in a mystery inside an enigma? I loved his ol’ 1-2. A simultaneous butt to 1 head and punch to 2 nuts. I’m still scratching my head over how he pulled off that move and without even attracting a warning.
Going back to your original point on honest nicknames, Evander "Bighorn" Holyfield, seems apt. For more than one reason if what I recall about the amount of children he fathered is true.
Wasn't simply the best moreso around his ring walk music - possibly the best out of the competitive UK scene at the time? I have to admit as a kid watching fight nights on ITV, with the build up to the ring walk, his cool demeanour and top rope vault whilst Tina was telling me that Chris was simply the best, lisp, Euro level competition and all, the easily impressioned boy watched with awe and thought Eubank was the dogs.