irrelative

adj

1. Having no relations to each other; unrelated.
2. Not related to the subject at hand; irrelevant.

   “When the subject of Mr. Denby fell of its own weight, he essayed other equally irrelative themes, but each time the very deference of Dick's attention seemed to paralyze him, and after a moment's stark pause the conversation that he had interrupted would go on without him.”

3. Describing two or more chords which do not share any notes in common.

   “Irrelative chords in music are those having no common tone.”