The definition of sick is to have an illness, to be tired of something or sorrowful about something.
(adjective)Sick is defined as a group of people collectively who are ill.
(noun)An example of sick is the group of people in a cancer wing in a hospital.
See sick in Webster's New World College Dictionary
adjective
Origin: ME sik, seke < OE seoc, akin to Ger siech < IE base *seug-, to be troubled or grieved > Arm hiucanim, (I) am weakening
transitive verb
See sick in American Heritage Dictionary 4
adjective sick·er, sick·est
Origin:
Origin: Middle English
Origin: , from Old English sēoc
.Learn more about sick