Here's what rhymes with immaterial.

Consider these alternatives

irrelevant / relevant incorporeal / territorial unimportant / important insubstantial / sample materiality / personality superfluous / thus ephemeral / general transpires / desires unmeasurable / preferable invulnerable / vulnerable arguable / inarguable ascertain / main undefined / find unrecognizable / advisable insignificant / significant specious / pieces corporeal / territorial inoperative / uncooperative causation / operation duplicates / states immeasurable / battle indistinguishable / distinguishable