Definition
This refers to insincere talk or promises that are unlikely to be fulfilled or have any practical result.
空話，大話
Those politicians' speeches all sounded like hot air, with no substance.
那些政客的演講聽起來都是空話，毫無實質內容。
He always says he will help, but those promises sound like a lot of hot air.
他總是說會幫忙，但那些承諾聽起來都是空話。
Don't pay attention to his boasting; it's all hot air.
別理會他的吹噓；那都是空話。