Trying to destroy or damage something, especially an established political system. (Cambridge Dictionary)
Seeking or intended to subvert an established system or institution. (Oxford Dictionaries)
Tending or intending to subvert or overthrow, destroy, or undermine an established or existing system, especially a legally constituted government or a set of beliefs. (Dictionary.com)
A systematic attempt to overthrow or undermine a government or political system by persons working secretly from within. (Merriam – Webster)
Who has been the most subversive person in history?
The ten most subversive women artists in history.