moot, moot point

There are two common meanings for the adjective moot:

• open to debate: This meaning is the traditional one, and moot is still used in this sense in Canadian and British English.
• of no practical importance: This newer meaning is well established in American usage and is widespread in Canadian English, as well.

Unfortunately, these two common meanings of moot are conflicting. If the phrase moot point is used to refer to an issue of no importance, then that issue is no longer worth debating. In this sense, moot point has a meaning almost directly opposite to its original meaning: “an issue open to debate.”

Therefore, to avoid confusing the reader, a writer must be careful to provide enough context so that it is obvious which meaning is intended.