noun
A person who rises up against authority, often in a political or military context. Slightly formal or news-reporting tone.
政府は造反者たちを鎮圧しようとした。
The government tried to suppress the rebels.
彼は党内の造反者と見なされている。
He is regarded as a rebel within the party.
謀反人 is a historical term for someone who plots rebellion, especially against a ruler or shogunate, and carries a stronger connotation of treason.
造反 (rebellion) + 者 (person). 造反 is a Sino-Japanese compound meaning 'to rebel' or 'to rise in revolt'.