Quick definitions from WordNet (sick)

▸ noun:  people who are sick ("They devote their lives to caring for the sick")
▸ verb:  eject the contents of the stomach through the mouth
▸ adjective:  not in good physical or mental health
▸ adjective:  feeling nausea; feeling about to vomit
▸ adjective:  affected with madness or insanity
▸ name:  A surname (very rare: popularity rank in the U.S.: #25098)

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▸ Also see sick