Axel: Double-tap right, Attack = Grand Uppercut

Not only is this the most devastating combination move in the game, but it also causes Axel to utter a totally incomprehensible shout.  What is it that he's saying?

To me he seems to be shouting "Razor Paw"! or possibly "Razor Claw"!  This to me made the move even more badass!

It's a made up word, like Shoyruken.

"Axel: Double-tap right, Attack = Grand Uppercut

Not only is this the most devastating combination move in the game, but it also causes Axel to utter a totally incomprehensible shout.  What is it that he's saying?
"

lol, i use this move combination all the time. I always thought he says "stfuuuppeercut"

He's saying Grand Upper. I'm sure I read somewhere confirming that, but it makes sense if you realise the guy saying it is speaking with a Japanese accent. Mythbusted! Though, for years, I thought it was 'Bare Knuckl-AH!'

hes saying. Grand UPPER!("Grand UPPAH!")

First of all, Shoryuken is not a made up word, it's Japanese. 

And I think GRAND UPPER is the closest approximation, probably because anything more complex would have been garbled by the Genesis' limited capacity. 

LMAO. I thought he originally said "Raptor Paw!" I was like, "wtf?"

As a young lad, I could have sworn that he was saying "Hit da floor".

Brass knuckle.  Just like on the arcade machines ;)