Noah Webster's Dictionary 1. (v. t.) To accuse falsely and maliciously of a crime or offense, or of something disreputable; to slander; to libel. 2. (v. i.) To propagate evil reports with a design to injure the reputation of another; to make purposely false charges of some offense or crime.

Multi-Version Concordance Calumniate (1 Occurrence) 1 Peter 3:16 having a good conscience, that as to that in which they speak against you as evildoers, they may be ashamed who calumniate your good conversation in Christ. (DBY)