Nonsensical is just used to define something as nonsense, so you would kind of think that sensical would define something as sense, however, this wouldn't work and the word doesn't appear to exist. I checked.
I suppose you couldn't or at least wouldn't (on grounds of the word not existing) say " That's sensical" as opposed to "That makes sense".
It sounds silly and i don't really know, so i'm just guessing.
I'm sure someone with a better grasp of the English language, such as Reg, could probably correct my guessing.
EDIT: Reg had already posted once i wrote my bollocks!
Come on Reg, you can't get away with that post!
