What is litmus test meaning?

A litmus test is a type of test that is used to determine someone's loyalty or suitability for a particular position or group. The term originated in chemistry, where litmus paper is used to test whether a substance is acidic or alkaline. In a political or social context, a litmus test might refer to a specific issue or belief that is seen as a defining characteristic of a particular ideology or group. For example, a litmus test for liberal Democrats might be support for healthcare reform, while a litmus test for conservative Republicans might be opposition to gun control. The term can also be used more broadly to refer to any kind of benchmark or metric that is used to evaluate someone's fitness or readiness for a particular task or role.