To switch allegiance to, affiliation with, or membership in, a country, political party, employer, club, etc. (for example, as a spy, soldier, politician, employee, club member, etc.).
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 turn against a previous affiliation or allegiance.
Used other than figuratively or idiomatically: see turn, coat.