Wiktionary
full of hot air
a. (context idiomatic English) talking a lot, especially without saying anything of value or meaning.
Usage examples of "full of hot air".
Whoever he was, he sounded full of himself, and also full of hot air.
Finally, when one of the others made a joking remark -- it was that I was so full of hot air he doubted if I really needed a balloon -- I sailed into him, and we fought furiously until we were dragged apart.
Finally, when one of the others made a joking remark it was that I was so full of hot air he doubted if I really needed a balloon-I sailed into him, and we fought furiously until we were dragged apart.