disloyal person; traitor
Refers to a person who betrays trust or loyalty, often in a feudal, organizational, or personal context. Somewhat formal or literary.
He went down in history as a disloyal person who betrayed his lord.
A disloyal person is unforgivable to the organization.
Compound of 不忠 (disloyalty) and 者 (person). The exact historical derivation is uncertain, but the word follows a standard Sino-Japanese pattern for describing a person with a certain trait.