He is so full of hot air.
full of hot air 直译过来就是：“充满了热空气”。在英语俚语中，hot air是“空话，大话和夸夸其谈”的意思。所以这个短语的正确意思是：“满口空话，吹牛，夸夸其谈”。因此，当美国人说”He is full of hot air.”时，他/她要表达的意思就是:”What he says is just empty talk.”、”He isshooting off his mouth.”、”What he says is alljaw.”。
Shirley: He is ready enough with his promises, but often fails to carry them out.
Jane: Just ignore him. He is full of hot air.
①He is generally regarded as a disgusting guy.
②What he said is simply not credible.
③Never believe in his commitment.
④Don’t listen to him.
1. be all jaw 全是空话，废话连篇
All this could be all jaw without a government that is unified in opinion.
What he said is all jaw.
2. commitment n. 承诺，保证
We made a commitment to keep working together.
They made a commitment to peace.
He made a commitment to pay the rent on time.