When it comes to describing the most evidential, the English language brings a plethora of synonyms to the table. Words like irrefutable, undeniable, indisputable, and conclusive can aptly describe information that is backed up by strong evidence. Additionally, you could opt for phrases like most compelling or most convincing to highlight the persuasive nature of the evidence presented. Other synonyms that revolve around the same theme of evidence include substantial, proven, factual, and reliable. However, it is up to the author or speaker to choose the right synonym for the context in which it is being used. Ultimately, using synonyms allows you to express the same idea with slightly different nuances, which can add depth and richness to your writing or conversation.