shut down

To close, terminate, or end.

“They are planning to shut down the entire building at the end of the month.”

To turn off or stop.

“It's a good idea to shut down the machine before you leave.”

To emotionally withdraw into oneself as a defense mechanism; to block out external stressors.

“I can't talk to him about a certain thing; he just shuts down anytime I try.”

(auto racing, car culture) To pass (another vehicle), especially quickly.