1.Definition: (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)"
2.Definition: not consisting of matter
"Immaterial apparitions", "Ghosts and other immaterial entities"
3.Definition: not pertinent to the matter under consideration
"The price was immaterial"
4.Definition: of no importance or relevance especially to a law case
"An objection that is immaterial after the fact"
5.Definition: without material form or substance