The Guardians Score is a comprehensive metric used by the Guardian Project to evaluate the privacy and security of Android applications. It analyzes various aspects of an app, including permissions requested, network activity, and the presence of trackers or potential vulnerabilities. The score, ranging from 0 to 100, provides a quick and easy-to-understand indication of an app's potential privacy risks, helping users make informed decisions about which apps to trust and use. A higher score generally indicates better privacy and security practices.