promise (one) the earth

promise (one) the earth

To promise someone something that is not feasible or cannot be done. Your clients will come to distrust you if you keep promising them the earth and then inevitably fail to deliver.
See also: earth, promise

promise the earth

If someone promises the earth, they promise to give people things that they cannot in fact possibly give them. `Politicians have lost credibility,' he complained, `they promise the earth and don't deliver.'
See also: earth, promise