A pool-shootin' boyby name ofWillie McCoy (but down home, they called him Slim), once told me that that is a term for a poolhustler or a pool shark. "Shyster" is a term generally referring to an unscrupulous ordiscreditable lawyer, politician, or anyperson who gets along using petty, sharp, unprofessional, and/or questionable methods. Shysters are oftensociopaths. The word itself derives from the German language word forhuman excrement.