Retire means to stop working or stop doing business. Usually, this means that someone has aged to the point where they want to stop working or that he or she has already made a fortune. You can retire, or you or something else can be retired by someone else.
Zelda had worked as a welder for more than forty years, and she had enjoyed every minute of it. But now that she was turning seventy, she decided that it was time to hang up her welding mask. She retired, and led a life of leisure.
After the baseball player Roberto Clemente died in a plane crash, his team decided to retire his jersey number, so that no other players on the team would ever wear the number twenty one.
Retiring, as a verb, can also mean going to bed, but as an adjective, it means shy and introverted.
Malcolm yawned and told us that he would be retiring shortly, since he had to get up for work very early the next morning. We all wished him a good night.
It was hard to get a fix on this new student, since she was so shy and retiring. She barely spoke at all for the first month she was in my class. It took a long time to get her to join in.
Halt means stop or cause to stop. Often, it is thought of as a military command, since when a sergeant wants his men to stop marching, he shouts "Halt!" If you decide that it is time for something to stop, you can say that you called a halt.
Private Pyle ended up having to do fifty push ups in front of the rest of the platoon because he didn't stop quickly enough when Sergeant Carter told the men to halt.
After it had been raining for almost twenty minutes with no signs of stopping, the officials decided to call a halt to the athletics meeting, and rescheduled it for another day.
Grind to a halt is an expression that means there is a slow down before stopping, but shudder to a halt means a very sudden stop.
Traffic grew thicker and thicker on the highway as our speed grew slower and slower, until eventually we ground to a halt. Every car, as far as the eye could see, was stationary.
The train wasn't going very fast, so when Marco pulled the emergency brake cord, it shuddered to a halt, knocking any standing passengers off of their feet.