: to make false: as
a : to make (as a document) false by mutilation, alteration, or addition [the motel clerk had falsified the records "M. A. Kelly"]
b : to report (as information) falsely [the informant falsified his testimony]
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.