`Johnny' was applied as a nickname for Confederate soldiers by the Federal soldiers in the American Civil War; `greyback' derived from their grey Confederate uniforms

a person who takes part in an armed rebellion against the constituted authority (especially in the hope of improving conditions)

someone who exhibits great independence in thought and action

take part in a rebellion; renounce a former allegiance

break with established customs

refusal to accept some authority or code or convention

organized opposition to authority; a conflict in which one faction tries to wrest control from another

resisting control or authority

discontented as toward authority

participating in organized resistance to a constituted government

in a rebellious manner

intentionally contemptuous behavior or attitude

an insubordinate act