Not consisting of matter; incorporeal; spiritual; disembodied.

Of no importance or minor effect.

without material form or substance; "an incorporeal spirit"

not consisting of matter; "immaterial apparitions"; "ghosts and other immaterial entities"

a rule of evidence that requires that the evidence must have a sufficient relationship to the issue in question

Evidence that is not admissible, because it makes no difference in the case at hand.

The common objection that specific evidence doesn't actually have any relevance to the case.

of no importance or relevance especially to a law case; "an objection that is immaterial after the fact"