[1] : The Collaborative International Dictionary of English v.0.48

sick \sick\, n.
   sickness. obs. --chaucer.
   1913 webster

[2] : The Collaborative International Dictionary of English v.0.48

sick \sick\, v. i.
   to fall sick; to sicken. obs. --shak.
   1913 webster

[3] : The Collaborative International Dictionary of English v.0.48

sick \sick\, a. compar. sicker; superl. sickest. oe. sek,
   sik, ill, as. se'oc; 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.
      1913 webster

            simon's wife's mother lay sick of a fever. --mark i.
                                                  30.
      1913 webster

            behold them that are sick with famine. --jer. xiv.
                                                  18.
      1913 webster

   2. affected with, or attended by, nausea; inclined to vomit;
      as, sick at the stomach; a sick headache.
      1913 webster

   3. having a strong dislike; disgusted; surfeited; -- with of;
      as, to be sick of flattery.
      1913 webster

            he was not so sick of his master as of his work.
                                                  --l'estrange.
      1913 webster

   4. corrupted; imperfect; impaired; weakned.
      1913 webster

            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.
      1913 webster

   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.
         1913 webster

   syn: diseased; ill; disordered; distempered; indisposed;
        weak; ailing; feeble; morbid.
        1913 webster
see also:
sicker sickest illness sick bay sick bed sick berth 
sick headache sick list sick room 

[4] : WordNet (r) 2.0

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
        upp, sickp, sick ofp, tired ofp
     n : people who are sick; "they devote their lives to caring for
         the 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
see also:
ill well nauseated queasy sickish brainsick 
crazy demented distracted disturbed mad 
unbalanced unhinged disgusted fed upp sickp 
sick ofp tired ofp vomit vomit up purge 
cast cat be sick disgorge regorge 
retch puke barf spew spue 
chuck upchuck honk regurgitate throw up 
keep down 

[5] : Moby Thesaurus II by Grady Ward, 1.0

180 moby thesaurus words for "sick":
   abnormal, affected, afflicted, ailing, airsick, amiss, annoyed,
   appalled, bad, below par, bent, bereft of reason, bizarre, blase,
   bored, brainsick, burdened, carsick, chagrined, comfortless,
   confined, crackbrained, cracked, crazed, crazy, critically ill,
   cronk, crook, daft, debilitated, defective, deluded, demented,
   deprived of reason, deranged, desolate, desole, disconsolate,
   diseased, disgusted, disordered, disoriented, dispirited,
   distraught, disturbed, down, faint, faintish, fed-up,
   feeling awful, feeling faint, feeling something terrible, fevered,
   flawed, flighty, forlorn, funny, ghoulish, good and tired,
   grotesque, gruesome, hallucinated, heartsick, heartsore, ill,
   imperfect, in danger, inconsolable, indisposed, infirm, insane,
   irked, irrational, irritated, jaded, kinky, laid low, laid up,
   life-weary, loco, lousy, lunatic, macabre, mad, maddened, manic,
   masochistic, mazed, mean, melancholic, melancholy, mental,
   mentally deficient, meshuggah, miserable, moon-struck, morbid,
   morose, mortally ill, nauseated, neurotic, non compos,
   non compos mentis, not all there, not quite right, not right, odd,
   of unsound mind, off, off-color, offended, out of sorts, peaked,
   peaking, peaky, peculiar, poorly, psycho, psychoneurotic,
   psychotic, put out, qualmish, queasy, queer, reasonless, repelled,
   repulsed, revolted, rocky, rotten, sadistic, satiated, seasick,
   seedy, senseless, shocked, shocking, sick at heart, sick of,
   sick unto death, sickened, sickish, sickly, soul-sick, splenetic,
   squeamish, stark-mad, stark-staring mad, strange, stricken,
   taken ill, tetched, tired, tired of, tired of living,
   tired to death, tottering, touched, troubled, unbalanced,
   unconsolable, unconventional, under the weather, unhealthy,
   unhinged, unsane, unsettled, unsound, unwell, upset, wandering,
   wearied, weariful, weary, weary unto death, weird, witless, wobbly,
   world-weary, wretched

Sick >> S Words
Sick, definition of term: Sick
sick_pag1.html

Sick Headache >> S Words
Sick Headache, definition of term: Sick Headache
sick+headache_pag1.html

Get Sick >> G Words
Get Sick, definition of term: Get Sick
get+sick_pag1.html