Sick  —adj. 1 esp. Us unwell, ill. 2 vomiting or likely to vomit. 3 (often foll. By of) colloq. A disgusted; surfeited. B angry, esp. Because of surfeit. 4 colloq. (of a joke etc.) Cruel, morbid, perverted, offensive. 5 a mentally disordered. B (esp. In comb.) Pining (lovesick). —n. Colloq. Vomit. —v. (usu. Foll. By up) colloq. Vomit.  take (or fall) sick colloq. Be taken ill. [old english]