What is Crimen Falsi?

Legal Definition
Civil law, crime. It is a fraudulent alteration, or forgery, to conceal or alter the truth, to the prejudice of another. This crime may, be committed in three ways, namely: 1. By forgery. 2. By false declarations or false oath, perjury. 3. By acts; as, by dealing with false weights and measures, by altering the current coin, by making false keys, and the like. Vide Dig. 48, 10, 22; Dig. 34, 8 2; Code, lib. 9, t. 22, 1. 2, 5, 9. 11, 16, 17, 23, and 24; Merl. Rep. h. t.; 1 Bro. Civ. Law, 426; 1 Phil. Ev. 26; 2 Stark. Ev. 715.

2. What is understood by this, term in the common law, is not very clearly defined. Peake's Ev. 133; 1 Phil. Ev. 24; 2 Stark. Ev. 715. It extends to forgery, perjury, subornation of perjury, suppression of testimony by bribery, and conspiracy to convict of perjury. See 12 Mod. 209; 2 S. & R. 552; 1 Greenl. Ev. 373; and article Faux.
-- Bouviers Law Dictionary
Legal Definition
In the civil law. The crime of falsifying; which might be committed either by writing, as by the forgery of a will or other instrument; by words, as by bearing false witness, or perjury; and by acts, as by counterfeiting or adulterating the public money, dealing with false weights and measures, counterfeiting seals, and other fraudulent and deceitful practices. Dig. 48, 10; Hallifax, Civil Law, b. 3, c, 12, nn. 56-59.

In Scotch law. It has been defined: "A fraudulent imitation or suppression of truth, to the prejudice of another." Ersk. Inst 4, 4, 66.

At common law. Any crime which may injuriously affect the administration of justice, by the introduction of falsehood and fraud. 1 Greenl. Ev. ยง 373.

In modern law. This phrase is not used as a designation of any specific crime, but as a general designation of a class of offenses, including all such as involve deceit or falsification; e, g., forgery, counterfeiting, using false weights or measures, perjury, etc. Includes forgery, perjury, subornation of perjury, and offenses affecting the public administration of justice. Matzenbaugh v. People, 194 111. 108, 62 N. E. 546, 88 Am. St Rep. 134; Little v. Gibson, 89 N. H. 510; State v. Randolph, 24 Conn. 365; Webb v. State, 29 Ohio St. 358; Johnston v. Riley, 13 Ga. 97.
-- Black's Law Dictionary
Legal Definition
The crime of falsifying, including perjury, forgery and the like. See 194 111. 108, 88 Am. St. Rep. 134, 62 N. E. 546.
-- Ballentine's Law Dictionary
Legal Definition
"Crime of falsifying". Forgery .