irrelevancy

The quality of being irrelevant or inapplicable; lack of pertinence or connection.

A thing that is irrelevant—having no bearing on the subject of discussion.

To believe that such talk really ever came out of people's mouths would be to believe that there was a time when time was of no value to a person who thought he had something to say; when it was the custom to spread a two-minute remark out to ten; when a man's mouth was a rolling-mill, and busied itself all day long in turning four-foot pigs of thought into thirty-foot bars of conversational railroad iron by attenuation; when subjects were seldom faithfully stuck to, but the talk wandered all around and arrived nowhere; when conversations consisted mainly of irrelevancies, with here and there a relevancy, a relevancy with an embarrassed look, as not being able to explain how it got there.

"You've been and taken my Japanese umbrella." "I won't have him making an exhibition of himself," said Cripps, ignoring the irrelevancy.