まことしやかまことしやかMeanings1na-adjectiveplausible but untrue; specious; seemingly truthfulusually written using kana aloneDescribes a statement, story, or claim that sounds believable but is actually false or deceptive. Often used with words like 嘘 (lie), 話 (story), or 言い訳 (excuse).彼かれはまことしやかな嘘うそをついた。He told a plausible lie.