worst / wərst/ • adj. superlative of bad, ill. ∎  of the poorest quality or the lowest standard: the speech was the worst he had ever made. ∎  least pleasant, desirable, or tolerable: they were to stay in the worst conditions imaginable. ∎  most severe, serious, or dangerous: at least 32 people died in Australia's worst bus accident. ∎  least suitable or advantageous: the worst time to take out a bond is when rates are low but rise suddenly.• adv. 1. superlative of badly, ill.2. most severely or seriously: manufacturing and mining are the industries worst affected by falling employment. ∎  least well, skillfully, or pleasingly: he was voted the worst dressed celebrity. ∎  used to introduce the fact or circumstance that the speaker considers most serious or unpleasant: her mother had rejected her, and worst of all, her adoptive father turned out to be a cheat and a deceiver.• n. the most serious or unpleasant thing that could happen: when I saw the ambulance outside her front door, I began to fear the worst. ∎  the most serious, dangerous, or unpleasant part or stage of something: there are signs that the recession is past its worst.• v. [tr.] (usu. be worsted) get the better of; defeat: this was not the time for a deep discussion—she was tired and she would be worsted.PHRASES: at its (or someone's) worst in the most unpleasant, unimpressive, or unattractive state of which someone or something is capable: nothing's working at the moment, so I suppose you've seen us at our worst. ∎  at the most severe or serious point or level: harsh lines appeared in his face when his rheumatism was at its worst.at worst (or the worst) in the most serious case: at worst the injury could mean months in the hospital. ∎  under the most unfavorable interpretation: the cabinet's reaction to the crisis was at best ineffective and at worst irresponsible.be one's own worst enemysee enemy.do one's worst (in the view of one's opponent) do as much damage as one can (often used to express defiance in the face of threats): let them do their worst—he would never surrender.get (or have) the worst of it be in the least advantageous or successful position; suffer the most.if worst comes to worst if the most serious or difficult circumstances arise.in the worst way inf. very much: he wants to win in the worst way.