Which word describes a fact that is indisputable and accepted without question?

The term that best describes a fact that is indisputable and accepted without question is "incontrovertible." This word is derived from the Latin "incontrovertibilis," indicating something that cannot be turned around or disputed. In the context of facts or truths, it refers to statements or evidence that are universally acknowledged and cannot reasonably be challenged due to existing proof or consensus.

When something is labeled as incontrovertible, it possesses a level of credibility and acceptance that makes it a reliable foundation for further discussion or argument. This characteristic is crucial in logical reasoning and critical thinking, where establishing common ground based on accepted facts is essential.

The other options, although they have their own meanings, do not convey the sense of undeniable truth that "incontrovertible" does. For instance, "fallacious" denotes something that is misleading or based on a mistaken belief. "Discordant" refers to a lack of harmony or agreement, often applied to sounds or opinions, while "dismal" describes something that is gloomy or depressing. None of these terms imply the certainty and acceptance that "incontrovertible" embodies.