Specious
Definition: having a false look of truth or genuineness
It comes from the Latin word meaning “beautiful.” The implication is that it’s something that looks good on the surface.
Why I Looked It Up
I was researching what to call things like The Lost Cause Argument or Donald Trump’s lies about the 2020 election. I posted a question to the English Stack Exchange, and this was one of the answers (actually, a comment).
Several people also mentioned “truthiness.”