What is the antonym of slogan?

There isn't a perfect one-word antonym for "slogan." However, depending on the context, these words could be considered opposites:

* Disclaimer: This is the closest in meaning, as a disclaimer is a statement that negates or contradicts a slogan's message.

* Refutation: This word implies a direct counter-argument to a slogan's claim.

* Denial: This word implies a refusal to accept or acknowledge a slogan's statement.

* Counter-argument: This is a broader term, referring to any argument that opposes a slogan's message.

The best antonym for "slogan" depends on the specific context and the intended meaning.