Source : Webster's Revised Unabridged Dictionary (1913)

Shyster \Shy"ster\, n. [Perh. from G. scheisse excrement.]
   A trickish knave; one who carries on any business, especially
   legal business, in a mean and dishonest way. [Slang, U.S.]

Source : WordNet®

shyster
     n : a person (especially a lawyer or politician) who uses
         unscrupulous or unethical methods [syn: {pettifogger}]