Worst (adjective)

1. The least favorable, desirable, or successful of two or more alternatives.
2. Being the most inferior, unpleasant, or severe of a group.

Origin:

From middle english worst, from old english weorst, meaning the same.

Examples:

1. The worst part of the trip was the long line at the airport.
2. The worst weather was on the day of the picnic.
3. The worst thing you can do is to give up.
4. The worst restaurant in town had terrible service and food.
5. The worst student in the class had the lowest grades and attendance.