Irreducibly means “in a way that cannot be made smaller or simpler.” You often put it in front of another describing word: two things are irreducibly different if you cannot mash them into one and still tell the truth. Writers and people in science use it; it is not a playground word. Though actually, a lot of the time people who say irreducibly just mean “really, at the bottom” — as in we are irreducibly human — which is a stretch from the strict “cannot be reduced” sense, but that is how it often lands.

無法再簡化地、無法再化約地