Saying someone is a murderer when he isn't is an example of slander.
When you tell everyone that an innocent man is a murderer, this is an example of when you slander the innocent man.
Origin of slander
- Middle English slaundre from Old French esclandre alteration of escandle from Latin scandalum cause of offense, stumbling block scandal
From American Heritage Dictionary of the English Language, 5th Edition
- 13th century. From Old French esclandre, from Ecclesiastical Latin scandalum (“stumbling block, temptation"), from Ancient Greek ÏƒÎºÎ¬Î½Î´Î±Î»Î¿Î½ (skandalon, “scandal").