When trying to convey the meaning of "most convicting," some synonyms that could be used include "compelling," "persuasive," "conclusive," "decisive," and "irrefutable." These words all suggest a high degree of certainty and clarity in the evidence or argument being presented. In a legal context, a "most convicting" piece of evidence would be one that is beyond doubt and could heavily influence a jury's decision. Outside of the legal world, these synonyms could also apply to any situation where a convincing argument or piece of evidence is needed to sway someone's opinion or make a strong case.