Here are some other words that convey a similar meaning:
* Indemonstrable: This word emphasizes the inability to provide evidence or proof.
* Infalsifiable: This word specifically refers to something that cannot be proven false, even though it might not be true.
* Unverifiable: This word highlights the impossibility of confirming or verifying something.
* Incontrovertible: This word is the opposite of unprovable, meaning something that is impossible to dispute or deny.
The most appropriate word will depend on the specific context.