A citizen or subject who unjustly and unlawfully takes up arms against the constituted authorities of the nation, to deprive them of the supreme power, either by resisting their lawful and constitutional orders, in some particular matter, or to impose on them conditions. Vattel, Droit des Gens, liv. 3, Section 328. In another sense it signifies a refusal to obey a superior, or the commands of a court. Vide Commission of Rebellion. The name of rebels is given to all subjects who unjustly take up arms against the ruler of the society, [or the lawful and constitutional government] whether their view be to deprive him of the supreme authority or to resist his lawful commands in some particular instance, and to impose conditions on him. Vatt. Law Nat bk. 3, I 288.
REBEL
TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.