noun
A somewhat formal or literary term for something that is not true; often used in abstract or philosophical contexts.
彼の主張は虚妄に過ぎない。
His claim is nothing more than a falsehood.
虚妄の世界に生きる。
Live in a world of lies.
嘘 is the common, everyday word for 'lie'. 虚妄 is more formal and abstract, often implying a fundamental untruth or illusion.
虚偽 is also a formal term for falsehood, but it is more commonly used in legal or official contexts (e.g., 虚偽の申告 'false declaration'). 虚妄 carries a stronger nuance of delusion or groundlessness.
Compound of 虚 (kyo, 'void, emptiness') and 妄 (mō, 'delusion, reckless'). The combination conveys the idea of something that is empty and delusory, hence 'falsehood' or 'untruth'.