calumny
noun, plural cal·um·nies.
1. a false and malicious statement designed to injure the reputation of someone or something:
The speech was considered a calumny of the administration.
2. the act of uttering calumnies; slander; defamation.
A word I've heard multiple conservative pundits use in the last few days to describe the Mueller report, and to describe its perpetuation of the "obstruction of justice" myth.