The process-oriented definition of an anarchist' is one who can anarchize, or anarchistically energize, a group, even if not a member. It often consists of organizing by resistance, e.g. troll-sysop struggle, which forces one's enemy to improve to the point where there is conflict along meaningful rather than trivial lines.
See how to organize an anarchist group for the more conventional definition which focuses on rejection of group entity power and of false community consisting of people whose hierarchy of risk sharing is designed to remain unequal, e.g. based on Sysop Vandal point of view and Wikimedia corruption.
To anarchize is to organize to a minimal degree that makes it impossible to organize or control something further. For instance, to establish a set of equal power relationships that act to prevent any usurpation of power later.