Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

  

promise sb the earth/moon

informal

Definition

to say that you will do much greater things than you will ever be able to achieve: Like most governments in their first term of office, they promised the earth.Making and breaking promises and commitments
(Definition of promise sb the earth/moon from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)