1. (adj)immaterial of no importance or relevance especially to a law case "an objection that is immaterial after the fact"
2. (adj)incorporeal, immaterial without materialform or substance "an incorporeal spirit"
3. (adj)immaterial, nonmaterial not consisting of matter "immaterial apparitions"; "ghosts and other immaterial entities"
4. (adj)extraneous, immaterial, impertinent, orthogonal not pertinent to the matter under consideration "an issue extraneous to the debate"; "the price was immaterial"; "mentioned several impertinent facts before finally coming to the point"
5. (adj)immaterial, indifferent (often followed by `to') lacking importance; not mattering one way or the other
"whether you choose to do it or not is a matter that is quite immaterial (or indifferent)"; "what others think is altogether indifferent to him"