The opposite of "am plausible" can be a range of negative adjectives, such as implausible, unbelievable, unlikely, dubious, incredible, and unconvincing. While the word "plausible" means that something is believable or credible, its antonyms imply that something lacks evidence or rationality to support its claims. It suggests that the statement is not trustworthy, accurate, or realistic. For example, an implausible argument is one that seems irrational or nonsensical, whereas an unbelievable story is one that seems too improbable to be true. Thus, understanding antonyms of "am plausible" can help us to evaluate the credibility of arguments, stories, or claims based on their logical coherence and realistic portrayal.