The person who carries out the final sentence or punishment.

A group that evaluates evidence to decide if someone is guilty or innocent.

When someone acts as "judge, jury, and executioner," they are combining three distinct roles into one: Interprets the "rules" and makes legal decisions.

The phrase is an English idiom used to describe a person or entity that has absolute, unilateral power to make decisions, determine guilt, and carry out punishment without any outside oversight or a fair legal process. Core Meaning