a moot point

What is the meaning of the expression "a moot point"?

A) A point that is debatable.
B) A point for which further debate is pointless.
C) A point about which one cannot speak.

You picked B, didn't you? Oddly, the answer is A. Dictionary.com states that moot is something that is subject to debate; arguable.

It doesn't mean C, something about which you cannot speak. A person who cannot speak is said to be mute, an entirely different concept. But some use the words interchangeably.

If you are one of them, consult a dictionary.