post·al 
/ˈpoʊstl̟/ adjective
always used before a noun /ˈpoʊstl̟/ adjective : relating to or involved in the sending, handling, and delivery of mail
▪ postal workers [=post office employees] ▪ Postal rates are going up. ▪ The city worked to quickly restore postal service.
▪ postal workers [=post office employees] ▪ Postal rates are going up. ▪ The city worked to quickly restore postal service.
go postal
US, informal : to suddenly behave in a very violent or angry way
▪ She suddenly went postal and started yelling at the customers. ▪ If he calls me this late again, I'm going to go postal on him.
▪ She suddenly went postal and started yelling at the customers. ▪ If he calls me this late again, I'm going to go postal on him.
