worst
noun
the least favorable outcome
“the worst that could happen”
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”
Oppositesbest
verb
defeat thoroughly
“He mopped up the floor with his opponents”
adjective
(superlative of `bad') most wanting in quality or value or condition
“the worst player on the team”
“the worst weather of the year”
Oppositesbest
adverb
to the highest degree of inferiority or badness
“She suffered worst of all”
“schools were the worst hit by government spending cuts”
Source: WordNet 3.1, Princeton University