adj. 1
In poor health; ill.
We have to care for the sick.
adj. 2
Having an urge to vomit.
My daughter was violently sick three times in the night.
adj. 3
In poor health; ill. [with with] Afflicted by (a specific condition, usually medical).
She was sick all day with the flu.
v. 1
To vomit.
I woke up at 4 am and sicked on the floor.

Related words

Word family: sickbay sicken sickening sickfic sickhouse sickish sickless sickly
Phrases: be sick take sick be taken sick sick and tired sick headache sick up call in sick fall sick

Forms

Sick or Sickness?

This distinction has received but a very limited acceptance in the United States, where sick and sickness have the earlier and wider usage.

J. C. Fernald, English Synonyms and Antonyms (1914)

Use in printed books, per decade from 1850 to 2019.

2 letters: ug
3 letters: bad¹, cat¹, ill¹, mad¹
4 letters: cast¹, weak¹, grim¹, puke¹, honk¹, spew¹, icky, barf¹, illy, spue
5 letters: crazy², funny², tired², upset², chuck¹, weary², purge¹, lousy², seedy², retch, tumid
6 letters: insane², poorly², peaked¹, morbid², unwell², ailing², sickly², grisly², infirm², queasy²
7 letters: twisted², invalid³, ghastly², macabre³, upchuck, sickish, regorge
8 letters: stricken², gruesome², diseased², nauseous², demented³, unhinged², disgorge², qualmish
9 letters: disturbed², unhealthy³, disgusted³, afflicted³, squeamish², nauseated⁴, brainsick
10 letters: unbalanced³, indisposed
11 letters: regurgitate⁴

The small number after each word is its number of syllables (crazy² = 2 syllables).