renegade
n. countablen. someone who leaves their group, country, or set of beliefs to join the other side. You use this for a person who refuses to follow the rules and acts independently.
n. a person who deserts and betrays an organisation, country, or set of principles. Often carries a connotation of rebellious independence or lawlessness.
The renegade soldier joined the enemy forces.
He was considered a renegade by his former colleagues after he leaked the company's secrets to the press.
The film depicts a renegade detective who ignores bureaucratic procedures to pursue a personal vendetta against the city's most powerful criminal syndicate.
From Spanish renegado, from Medieval Latin renegātus, perfect participle of renegō (“I deny”). See also renege.
Often used attributively as a modifier before another noun (e.g., 'renegade priest').