Idiom of the day :- Hot air

Usage, examples and definition of the Idiom :-

‘Elect me and I promise I will reduce taxes, shorten the work week, and see to it that everyone gets paid a higher wage,’ Blah declared. ‘Blah is full of hot air,’ Someone said. ‘Yes, and everything he says is hot air,’ another replied. Promises and boasts that won’t or can’t be kept are called hot air.