Worst has 11 different meanings across 4 categories:
the greatest damage or wickedness of which one is capable
"the invaders did their worst"
"so pure of heart that his worst is another man's best"
the weakest effort or poorest achievement one is capable of
"it was the worst he had ever done on a test"
something or someone that is the worst
"After trying every restaurant in town, we finally found the worst place for food."
In plain English: The worst is the person who causes the most trouble or gets into the biggest amount of problems.
"He knows he made the worst mistake of his life when he decided to quit without telling anyone."
To make worse.
"Don't add salt to the soup, you'll just make it worst."
In plain English: To be worst means to fail at something more than anyone else.
"The storm worsted our defenses and knocked out the power across the entire city."
(superlative of `bad') most wanting in quality or value or condition
"the worst player on the team"
"the worst weather of the year"
superlative form of bad: most bad
"After waiting three hours for a table, that restaurant was definitely the worst place we've ever eaten at."
Most inferior; doing the least good.
"Among all the candidates for the volunteer position, his proposal proved to be the worst since it offered no benefit whatsoever to the community."
In plain English: Worst is the adjective used to describe something that is the most bad or unpleasant possible.
Usage: Use worst as an adjective before a noun, such as in "the worst day," or after a linking verb to describe something that has reached its lowest point. Avoid using it with comparative adverbs like "more" since superlatives already indicate the extreme degree of badness.
to the highest degree of inferiority or badness
"She suffered worst of all"
"schools were the worst hit by government spending cuts"
"the worst dressed person present"
superlative form of bad: most bad
"After months of rain, yesterday was definitely the worst day for camping we've ever had."
In plain English: Worst means to the greatest degree of badness or failure.
"We had our worst time ever at that party."
The word "worst" comes from the Middle English superlative form of "bad," which itself traces back to the Proto-Germanic root for evil. It entered modern usage as the comparative and superlative forms evolved alongside its related word, "worse."