1. unimportant under the circumstances; irrelevant:

«…にとって» 重要でない, 取るに足らない «to»

e.g. so long as the band kept the beat, what they played was immaterial.

2. Philosophy spiritual, rather than physical:

非物質的な, 無形の; 霊的な(↔ material)

e.g. we have immaterial souls.

immateriality |ˌi(m)məˌtirēˈalədē| noun

immaterially adverb

Immaterial and irrelevant are familiar in legal, especially courtroom, use. Immaterial means ‘unimportant because not adding anything to the point.’ Irrelevant, a much more common word, means ‘beside the point, not speaking to the point.’ Courts have long ceased to demand precise distinctions, and evidence is often objected to as “immaterial, irrelevant, and incompetent (‘offered by a witness who is not qualified to offer it’).”.

late Middle English (in immaterial (sense 2)): from late Latin immaterialis, from in- ‘not’ + materialis ‘relating to matter’.