superlative of bad adjective : of the lowest quality, or the most unpleasant, difficult, or severe:
That was the worst meal I've ever eaten.
Oxford Essential Dictionary
adjective, adverb (bad, worse, worst)
the least pleasant or suitable; the least well:
He's the worst player in the team!
That was the worst day of my life.
Everyone played badly, but I played worst of all.
opposite best
Longman Dictionary of Contemporary English
worst
I. worst1 /wɜːst $ wɜːrst/ BrE AmE adjective [the superlative of bad]
[Language: Old English; Origin: wierresta, wyrsta]
1. [only before noun] worse than anything or anyone else ⇨ best:
This is the worst recession for fifty years.
My worst fear was that we would run out of food.
What is the worst possible thing that can happen?
2. be your own worst enemy to cause a lot of problems for yourself because of your own behaviour
3. come off worst to lose a fight or argument
Oxford Advanced Learner's Dictionary
worst
worst [worst worsts worsted worsting] adjective, adverb, noun, verb [wɜːst] [wɜːrst]
adjective (superlative of bad)
of the poorest quality or lowest standard; worse than any other person or thing of a similar kind
• It was by far the worst speech he had ever made.
• What's the worst thing that could happen?
• What she said confirmed my worst fears (= proved they were right).
Word Origin:
Old English wierresta, wyrresta (adjective), wierst, wyrst (adverb), of Germanic origin; related to worse.
Idioms: at worst ▪ bring out the worst in somebody ▪ come off worst ▪ do your worst ▪ get the worst of it ▪ if the worst comes to the worst ▪ worst of all worlds ▪ your own worst enemy
Cambridge Advanced Learner's Dictionary
worst / wɜːst / / wɝːst / adjective
A2 superlative of bad adjective : of the lowest quality, or the most unpleasant, difficult, or severe:
That was the worst meal I've ever eaten.
"It was the worst moment of my life," she admitted.
He is my worst enemy .
Collins Advanced Learner’s English Dictionary
worst
[wɜ͟ː(r)st]
1) Worst is the superlative of bad.
2) Worst is the superlative of badly.
3) N-SING: the N, oft N of n The worst is the most unpleasant or unfavourable thing that could happen or does happen.
Though mine safety has much improved, miners' families still fear the worst...
The country had come through the worst of the recession.
Ant:
best
4) Worst is used to form the superlative of compound adjectives beginning with `bad' and `badly'. For example, the superlative of `badly-affected' is `worst-affected'.
5) PHRASE: PHR with cl You say worst of all to indicate that what you are about to mention is the most unpleasant or has the most disadvantages out of all the things you are mentioning.
The people most closely affected are the passengers who were injured and, worst of all, those who lost relatives.
6) PHRASE: PHR with cl/group You use at worst or at the worst to indicate that you are mentioning the worst thing that might happen in a situation.
At best Nella would be an invalid; at worst she would die...
At the worst he would be there by the following night.
7) PHRASE: n PHR, PHR after v, v-link PHR When someone is at their worst, they are as unpleasant, bad, or unsuccessful as it is possible for them to be.
This was their mother at her worst. Her voice was strident, she was ready to be angry at anyone.
8) PHRASE: V inflects, PHR with cl You use if the worst comes to the worst to say what you might do if a situation develops in the most unfavourable way possible. The form if worst comes to worst is also used, mainly in American English.
If the worst comes to the worst I guess I can always ring Jean...
He was asked whether he would walk out if the worst came to the worst.
9) PHRASE: V inflects If someone does their worst, they do everything unpleasant that they can possibly do. You can say `do your worst' to show someone that you are not frightened of what they may do.
I think it was dangerous to say: look, we've got an army now - do your worst.
Merriam-Webster's Advanced Learner's Dictionary
1worst /ˈwɚst/ adj superlative form of 1bad
1 a : worse than all others
• This is the worst car I've ever bought.
• In my opinion, it's her worst book.
• It was the worst movie I've ever seen.
• His worst quality is his impatience.
• This has got to be the worst day of my life.
• The worst part of working there is the long commute.
• My worst fears came true.
• I am my own worst critic. [=I criticize my work more harshly than anyone else]
• He lives in the worst area of the city.
b : least skillful, talented, or successful
• He is the worst singer I've ever heard.
• They're the worst team ever.
2 : least appropriate, useful, or helpful
• That is the worst advice I've ever heard.
• I'm having the worst luck today.
• Leaving now is the worst thing you could do.
• He is the worst person to ask for advice.
• You've picked the worst time to come over.
• She called at the worst possible moment.
in the worst way US informal : very much
• I want a new bike in the worst way.
worst of all
- used to refer to the least pleasant or appealing part of something that has many bad parts
• I forgot my backpack, was late for class, and worst of all, I studied the wrong material for the test.
your own worst enemy
- see enemy