WordNet sense 1 (having only a limited ability to react chemically; chemically inactive):

indifferent, inert

WordNet sense 2 (not reacting chemically):

unreactive

WordNet sense 3 (having no net electric charge; not electrified):

electroneutral

WordNet sense 4 (having no personal preference):

impersonal

WordNet sense 5 (undistorted by emotion or personal bias; based on observable phenomena):

objective, nonsubjective

WordNet sense 6 (lacking any sense of moral standards or principles):

amoral, unmoral

WordNet sense 7 (not affiliated with any faction, party, or cause):

nonaligned

WordNet sense 8 (lacking in variety and interest):

colorless, colourless

WordNet sense 9 (having no hue):

achromatic