Verb
To begin to behave in an erratic, uncontrolled, dangerous, destructive, or savage way.
To behave in a very unconventional, independent, uncontrolled, or unauthorized way that ignores rules, norms, or expectations.
To defect, or to repudiate allegiance, fealty, affiliation, or membership. (For example, a spy or soldier in relation to a country; or a politician in relation to a political party; or an employee; or a club member.)