Source : Webster's Revised Unabridged Dictionary (1913)

Worst \Worst\, a., superl. of {Bad}. [OE. werst, worste, wurste,
   AS. wyrst, wierst, wierrest. See {Worse}, a.]
   Bad, evil, or pernicious, in the highest degree, whether in a
   physical or moral sense. See {Worse}. ``Heard so oft in worst
   extremes.'' --Milton.

         I have a wife, the worst that may be.    --Chaucer.

         If thou hadst not been born the worst of men, Thou
         hadst been a knave and flatterer.        --Shak.

Worst \Worst\, n.
   That which is most bad or evil; the most severe, pernicious,
   calamitous, or wicked state or degree.

         The worst is not So long as we can say, This is the
         worst.                                   --Shak.

         He is always sure of finding diversion when the worst
         comes to the worst.                      --Addison.

Worst \Worst\, v. t. [imp. & p. p. {Worsted}; p. pr. & vb. n.
   {Worsting}.] [See {Worse}, v. t. & a.]
   To gain advantage over, in contest or competition; to get the
   better of; to defeat; to overthrow; to discomfit.

         The . . . Philistines were worsted by the captivated
         ark.                                     --South.

Worst \Worst\, v. i.
   To grow worse; to deteriorate. [R.] ``Every face . . .
   worsting.'' --Jane Austen.

Bad \Bad\ (b[a^]d), a. [Compar. {Worse}; superl. {Worst}. ]
   [Probably fr. AS. b[ae]ddel hermaphrodite; cf. b[ae]dling
   effeminate fellow.]
   Wanting good qualities, whether physical or moral; injurious,
   hurtful, inconvenient, offensive, painful, unfavorable, or
   defective, either physically or morally; evil; vicious;
   wicked; -- the opposite of {good}; as, a bad man; bad
   conduct; bad habits; bad soil; bad health; bad crop; bad
   news.

   Note: Sometimes used substantively.

               The strong antipathy of good to bad. --Pope.

   Syn: Pernicious; deleterious; noxious; baneful; injurious;
        hurtful; evil; vile; wretched; corrupt; wicked; vicious;
        imperfect.

Source : WordNet®

worst
     adj : (superlative of `bad') most wanting in quality or value or
           condition; "the worst player on the team"; "the worst
           weather of the year" [ant: {best}]

worst
     n 1: the least favorable outcome; "the worst that could happen"
     2: 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"
     3: the weakest effort or poorest achievement one is capable of;
        "it was the worst he had ever done on a test" [ant: {best}]
     adv : 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"
     v : defeat thoroughly; "He mopped up the floor with his
         opponents" [syn: {pip}, {mop up}, {whip}, {rack up}]

worst
     See {bad}

bad
     adj 1: having undesirable or negative qualities; "a bad report
            card"; "his sloppy appearance made a bad impression";
            "a bad little boy"; "clothes in bad shape"; "a bad
            cut"; "bad luck"; "the news was very bad"; "the
            reviews were bad"; "the pay is bad"; "it was a bad
            light for reading"; "the movie was a bad choice" [ant:
             {good}]
     2: very intense; "a bad headache"; "in a big rage"; "had a big
        (or bad) shock"; "a bad earthquake"; "a bad storm" [syn: {big}]
     3: feeling physical discomfort or pain (`tough' is occasionally
        used colloquially for `bad'); "my throat feels bad"; "she
        felt bad all over"; "he was feeling tough after a restless
        night" [syn: {tough}]
     4: (of foodstuffs) not in an edible or usable condition; "bad
        meat"; "a refrigerator full of spoilt food" [syn: {spoiled},
         {spoilt}]
     5: not capable of being collected; "a bad (or uncollectible)
        debt" [syn: {uncollectible}]
     6: below average in quality or performance; "a bad chess
        player"; "a bad recital"
     7: nonstandard; "so-called bad grammar"
     8: not financially safe or secure; "a bad investment"; "high
        risk investments"; "anything that promises to pay too much
        can't help being risky"; "speculative business
        enterprises" [syn: {insecure}, {risky}, {high-risk}, {speculative}]
     9: physically unsound or diseased; "has a bad back"; "a bad
        heart"; "bad teeth"; "an unsound limb"; "unsound teeth"
        [syn: {unfit}, {unsound}]
     10: capable of harming; "bad habits"; "bad air"; "smoking is bad
         for you"
     11: keenly sorry or regretful; "felt bad about letting the team
         down"; "was sorry that she had treated him so badly";
         "felt bad about breaking the vase" [syn: {sorry}]
     12: characterized by wickedness or immorality; "led a very bad
         life" [syn: {immoral}]
     13: reproduced fraudulently; "like a bad penny..."; "a forged
         twenty dollar bill" [syn: {forged}]
     14: not working properly; "a bad telephone connection"; "a
         defective appliance" [syn: {defective}]
     [also: {worst}, {worse}]

bad
     n : that which is below standard or expectations as of ethics or
         decency; "take the bad with the good" [syn: {badness}]
         [ant: {good}, {good}]
     [also: {worst}, {worse}]

bad
     adv 1: with great intensity (`bad' is a nonstandard variant for
            `badly'); "the injury hurt badly"; "the buildings were
            badly shaken"; "it hurts bad"; "we need water bad"
            [syn: {badly}]
     2: very much; strongly; "I wanted it badly enough to work hard
        for it"; "the cables had sagged badly"; "they were badly
        in need of help"; "he wants a bicycle so bad he can taste
        it" [syn: {badly}]
     [also: {worst}, {worse}]