Synonyms for Falsify (same or very similar meaning)
WordNet sense 1 (fake or falsify):
cook, fake, fudge, manipulate, misrepresent, wangleWordNet sense 2 (make false by mutilation or addition; as of a message or story):
distort, garble, warpWordNet sense 3 (insert words into texts, often falsifying it thereby):
alter, interpolateFrom the ODE community, based on WordNetadd/edit