What is a "moot point"?

ScottsEnglish

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

A "moot point" is something that does not matter any longer, because the facts have changed. 

For example, "The car manufacturer fixed the car's defect, but it's a moot point because no one will buy the car now.", or, "The city built a new parking lot, but the company moved its headquarters outside of town, so it's a moot point.

Be careful not to confuse mute with moot. Mute means cannot speak, or extremely quiet, while moot means irrelevant or impossible to decide.