swagのようなどんな単語でも探してください。
 
1.
To lash out violently and at random, often in a blind rage. Term taken from the 1990's incidents of workplace violence involving US Postal System workers.
I was so angry at work with the new workload, I was afraid I'd go postal.
Unidyneによって 2005年03月11日(金)
 
2.
To exact calculated revenge on co-workers or schoolmates, usually with a firearm, after being fired or expelled or just feeling extremely hard-done-by.

Software tester Michael McDermott shot and killed seven co-workers in 2000 after having his pay docked to cover back taxes.
A disgruntled former worker went postal today leaving seven dead, including two accountants he had accused of being 'Nazis' the day before.
beeによって 2005年03月22日(火)
 
3.
to succumb to fatigue and tension, to be become violently angry(from a series of incidents from the mid 80s to the 90s where various postal workers went on shooting rampages)
I will not let him go postal in plain sight.
The Return of Light Jokerによって 2008年07月10日(木)
 
4.
To loose touch with someone for a long time. Not talk to someone in a while.
You go postal on me all the time and I only hear from you every 3 months.
Boopboopによって 2007年06月03日(日)