Antonyms for "be plausible" can be more appropriately stated as "be implausible" or "be unbelievable." "Implausible" refers to something that is not conceivable or believable, while "unbelievable" denotes something that is not credible or trustworthy. Employing antonyms for "be plausible" refers to questioning the possibility or feasibility of an idea or concept. As a writer, it is essential to understand antonyms to create balanced and effective writing. Using antonyms helps provide clarity and emphasis on different perspectives, especially when presenting a counter-argument or expressing a contradictory position. In summary, antonyms for "be plausible" reflect opinions or perspectives that contradict the likelihood or possibility of an idea or concept.