The term 'dying earth' typically refers to a planet or world that is reaching the end of its existence. A range of synonyms can be used in place of the phrase 'dying earth', such as 'decaying planet', 'expiring world', or 'waning sphere'. Other options include 'fading orb', 'failing celestial body', and 'diminishing globe'. The use of these synonyms can add variation to written or spoken language and help to create a more nuanced message. These terms also evoke different emotions or associations with the impending end of the planet or world, allowing writers and speakers to convey a specific tone or mood.