Question

Full of Hot Air being foolish and talking nonsense; pompous; vain

Accepted Answer

I don't believe a word he says. He's full of hot air. When you talk, warm air comes out of your mouth. Large balloons that carry people in baskets are kept afloat by hot air. This idiom from the mid-1800s puts those two ideas together. If you want to describe a pompous person who is all puffed up (like a balloon), you could say he or she is "full of hot air" (that's coming out of his or her mouth).

Idiom	Full of Hot Air
Example	I don't believe a word he says. He's full of hot air.
Meaning	being foolish and talking nonsense; pompous; vain
Origin	When you talk, warm air comes out of your mouth. Large balloons that carry people in baskets are kept afloat by hot air. This idiom from the mid-1800s puts those two ideas together. If you want to describe a pompous person who is all puffed up (like a balloon), you could say he or she is "full of hot air" (that's coming out of his or her mouth).

Hot Air Full I Word Foolish Talking Nonsense