A blind guess is an estimate or assumption made without any factual evidence or knowledge. Synonyms for this phrase include conjecture, speculation, supposition, presumption, and assumption. Each of these words suggests a different level of confidence or doubt in the accuracy of the guess. For instance, conjecture implies an educated guess based on some information or knowledge, while supposition suggests a more uncertain or hypothetical assumption. The word presumption is often used in a legal context and implies a belief or assumption that something is true without proof. Regardless of which synonym is used, a blind guess is often made in situations where there is insufficient information to make an informed decision.