Or perhaps when someone cites the definition of "calumny" to you (not against anyone), that person is trying to point out you have yet to support one single allegation you're levying.

To continue constitutes

https://en.oxforddictionaries.com/definition/slander

which is, of course, a sin.

"He was not a stupid person", for example, proves absolutely nothing and does not support the conclusion "that he must have known about the Vatican Bank".