Revolutionary- A fundamental change in the way of thinking about or visualizing something : a change of paradigm.
Jesus of Nazareth-
His teaching was revolutionary - it upset the establishment and He made them look fools in public, He went to people they were afraid to touch (eg lepers), and actually spoke to and healed Gentiles, of all people.
The scribes and Pharisees hated his parables, which always seemed to put them in the wrong.
He called the religious leaders (the Scribes, Pharisees, and Sadduccees), hypocrites. The hated and detested Roman conquerors permitted these men to keep their power and authority so long as they kept their people in line. ( A modern parallel would be with the occupying German conquerors of France using French collaborators to rule their own people, who hated them [and killed many when their German protectors left.] ) Along comes this young Rabbi who tells the crowd that they are hypocrites, blind, serpents, and vipers: not exactly tactful - they would have hated Him for it - but the crowd would have lapped it up.
The rulers plotted to kill Jesus, and you don't do this unless you are a threat to the establishment that cannot be dealt with any other way.
The establishment tried to prevent His followers of this sect with revolutionary beliefs spreading their message and getting more adherents.
Jesus proved His revolutionary doctrines and beliefs through His own resurrection from the dead . A revolution is basically where old ideas are replaced by new. In the same way, the establishment refuses to believe that they are often the cause of revolutions in the first place, and deals with revolutionaries by killing them and their followers.
In summary, Jesus had greatly upset the ruling caste, cost them a lot of money and custom, made people think, upset the status-quo, pleased the masses, stressed their hypocrisy, beat their arguments, and most of all He was always right, so He had to go. Active planning on how to set Him up and kill Him had already started a year before His arrest.
Jesus was a revolutionary in the sense that He introduced new ideas, new thoughts and ways of doing things, and upset the establishment. In that sense He was most definitely a revolutionary, and had to die.