implausible
adj.not likely to be true or possible. You use this to describe a story or an explanation that seems very strange or hard to believe.
adj.unlikely to be true or possible; not credible. Often used to describe narratives, arguments, or explanations that lack sufficient evidence or logical consistency.
“The story of a giant rabbit is implausible.”
“The suspect's alibi was implausible because he claimed to be at a quiet library while the crime was happening in a busy city center.”
“While the theory provides a useful framework for understanding the data, the final conclusion remains implausible given the lack of supporting evidence from the field trials.”
“The man couldn’t change a light bulb by himself … His death scenario is completely implausible to everybody that knew him.” 411: Did Epstein’s cellmate know too much?”
From im- + plausible.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.