Sick

adj. ill, suffering from a disease or illness; nauseous, feeling the need to vomit; disgusted, fed up; pertaining to a sickness, pertaining to a disease; yearning, longing; infected with bacteria or microorganisms (Agriculture)

n. people who are ill, sick people collectively

To be sick can mean:Having a disease or illness. This is the original meaning.The act of vomiting.Sick may also refer to:Sick (magazine), a humour magazineSick (Sow album), an album by SowSick (Massacra album), an album by MassacraSICK AG, a German sensor technology corporation which built the laser range-finders used on the robot StanleyTo set a dog on something: this arose from the command "sic 'im" as a quick pronunciation of "seek 'im".
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Noun
1. people who are sick; "they devote their lives to caring for the sick"
(hypernym) people
(derivation) vomit, vomit up, purge, cast, cat, be sick, disgorge, regorge, retch, puke, barf, spew, spue, chuck, upchuck, honk, regurgitate, throw up
Verb
1. 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"
(synonym) vomit, vomit up, purge, cast, cat, be sick, disgorge, regorge, retch, puke, barf, spew, spue, chuck, upchuck, honk, regurgitate, throw up
(hypernym) excrete, egest, eliminate, pass
Adjective
1. not in good physical or mental health; "ill from the monotony of his suffering"
(synonym) ill
(similar) afflicted, stricken
(see-also) unhealthy
2. feeling nausea; feeling about to vomit
(synonym) nauseated, queasy, sickish
(similar) ill
3. affected with madness or insanity; "a man who had gone mad"
(synonym) brainsick, crazy, demented, distracted, disturbed, mad, unbalanced, unhinged
(similar) insane
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"
(synonym) disgusted, fed up(p), sick(p), sick of(p), tired of(p)
(similar) displeased

(v. i.)
To fall sick; to sicken.
  

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

(superl.)
Corrupted; imperfect; impaired; weakned.
  

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

(superl.)
Affected with disease of any kind; ill; indisposed; not in health. See the Synonym under Illness.
  

(n.)
Sickness.
  

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( Sinus node disease )
Sick sinus syndrom is caused by ischemia,infarction or degenerative disease of the sinus node it is characterized by long intervals bitween cosecutive "P" waves( >2 seconds) on the ECG.
This sinus block or bradycardia may allow cardiac tachyarrythmias to emerge.Acombination of fast and slow supraventricular rhythms as known as "tachy-brady" syndrome.