incontrovertible - certain
Something ‘incontrovertible’ is not open to question or argument because it is absolutely correct or definite. The word itself when broken down essentially means 'without controversy' as it is typically applied to something obviously true, but there are some instances where people erroneously or deceitfully call something incontrovertible in order to support a cause or advance their own interests.
The police are highly confident of securing a conviction because they have incontrovertible evidence that the suspect is guilty.
Unable to hide her bias, the journalist said that it was incontrovertibly true that the politician took a bribe even though the investigation into it is still ongoing.
I won the debate because I presented incontrovertible facts which simply could not be accurately argued against.