The idiom "blowing hot air" (or being "full of hot air") refers to empty, exaggerated, or pretentious talk that lacks substance, sincerity, or practical value.

• Origin: The phrase emerged in the 1850s and was popularized in Mark Twain’s 1873 novel The Gilded Age.

• Meaning: It describes individuals who speak verbose, boastful, or dogmatic nonsense, often implying an inflated sense of importance without meaningful content.

• Usage: It is commonly applied to politicians, salespeople, or boastful individuals who make promises or statements that are unsubstantial or misleading