1) the crime of creating a false document, altering a document, or writing a false signature for the illegal benefit of the person making the forgery. this includes improperly filling in a blank document, like an automobile purchase contract, over a buyer’s signature, with the terms different from those agreed. it does not include such innocent representation as a staff member autographing photos of politicians or movie stars. while similar to forgery, counterfeiting refers to the creation of phoney money, stock certificates or bonds which are negotiable for cash. 2) a document or signature falsely created or altered.