A person who participates in a rebellion or uprising against authority.
反乱者たちは城を占拠した。
The rebels occupied the castle.
The government dispatched troops to suppress the insurgents.
Standard kanji spelling using 反 (anti-) and 乱 (revolt).
Variant spelling using 叛 (rebel); less common but still seen.
Compound of 反乱 (rebellion) + 者 (person). The kanji 反 means 'anti-' or 'oppose', 乱 means 'disorder' or 'revolt', and 者 is a common suffix for 'person'.