Source : Webster's Revised Unabridged Dictionary (1913)

Sick \Sick\, v. i.
   To fall sick; to sicken. [Obs.] --Shak.

Sick \Sick\, a. [Compar. {Sicker}; superl. {Sickest}.] [OE. sek,
   sik, ill, AS. se['o]c; akin to OS. siok, seoc, OFries. siak,
   D. ziek, G. siech, OHG. sioh, Icel. sj?kr, Sw. sjuk, Dan.
   syg, Goth. siuks ill, siukan to be ill.]
   1. Affected with disease of any kind; ill; indisposed; not in
      health. See the Synonym under {Illness}.

            Simon's wife's mother lay sick of a fever. --Mark i.
                                                  30.

            Behold them that are sick with famine. --Jer. xiv.
                                                  18.

   2. Affected with, or attended by, nausea; inclined to vomit;
      as, sick at the stomach; a sick headache.

   3. Having a strong dislike; disgusted; surfeited; -- with of;
      as, to be sick of flattery.

            He was not so sick of his master as of his work.
                                                  --L'Estrange.

   4. Corrupted; imperfect; impaired; weakned.

            So great is his antipathy against episcopacy, that,
            if a seraphim himself should be a bishop, he would
            either find or make some sick feathers in his wings.
                                                  --Fuller.

   {Sick bay} (Naut.), an apartment in a vessel, used as the
      ship's hospital.

   {Sick bed}, the bed upon which a person lies sick.

   {Sick berth}, an apartment for the sick in a ship of war.

   {Sick headache} (Med.), a variety of headache attended with
      disorder of the stomach and nausea.

   {Sick list}, a list containing the names of the sick.

   {Sick room}, a room in which a person lies sick, or to which
      he is confined by sickness.

   Note: [These terms, sick bed, sick berth, etc., are also
         written both hyphened and solid.]

   Syn: Diseased; ill; disordered; distempered; indisposed;
        weak; ailing; feeble; morbid.

Sick \Sick\, n.
   Sickness. [Obs.] --Chaucer.

Source : WordNet®

sick
     adj 1: not in good physical or mental health; "ill from the
            monotony of his suffering" [syn: {ill}] [ant: {well}]
     2: feeling nausea; feeling about to vomit [syn: {nauseated}, {queasy},
         {sickish}]
     3: affected with madness or insanity; "a man who had gone mad"
        [syn: {brainsick}, {crazy}, {demented}, {distracted}, {disturbed},
         {mad}, {unbalanced}, {unhinged}]
     4: having a strong distaste from surfeit; "grew more and more
        disgusted"; "fed up with their complaints"; "sick of it
        all"; "sick to death of flattery"; "gossip that makes one
        sick"; "tired of the noise and smoke" [syn: {disgusted}, {fed
        up(p)}, {sick(p)}, {sick of(p)}, {tired of(p)}]

sick
     v : eject the contents of the stomach through the mouth; "After
         drinking too much, the students vomited"; "He purged
         continuously"; "The patient regurgitated the food we gave
         him last night" [syn: {vomit}, {vomit up}, {purge}, {cast},
          {cat}, {be sick}, {disgorge}, {regorge}, {retch}, {puke},
          {barf}, {spew}, {spue}, {chuck}, {upchuck}, {honk}, {regurgitate},
          {throw up}] [ant: {keep down}]

sick
     n : people who are sick; "they devote their lives to caring for
         the sick"