Synonyms for Untrue (same or very similar meaning)
WordNet sense 1 (not in accordance with the fact or reality or actuality):
falseWordNet sense 2 (not accurately fitted; not level):
out of trueWordNet sense 3 (not even or uniform as e.g. in shape or texture):
unevenWordNet sense 4 (likely to change frequently often without apparent or cogent reason; variable):
inconstantFrom the ODE community, based on WordNetadd/edit