exaggerated talk; empty boasting
Rare, literary term for speech that is inflated or untruthful; not used in everyday conversation.
His story was nothing but empty boasting, and no one believed it.
Compound of 虚 (false, empty) and 誕 (birth, but here likely used for its sound or extended meaning related to boasting). The exact derivation is uncertain; it is a rare Sino-Japanese word.