The Collaborative International Dictionary of English v.0.48:

Gyp \Gyp\ (j[i^]p), n. [Said to be a sportive application of Gr.
   gy`ps a vulture.]
   A college servant; -- so called in Cambridge, England; at
   Oxford called a scout. [Cant]
   [1913 Webster]

WordNet (r) 3.0 (2006):

gyp
    n 1: a swindle in which you cheat at gambling or persuade a
         person to buy worthless property [syn: bunco, bunco
         game, bunko, bunko game, con, confidence trick,
         confidence game, con game, gyp, hustle, sting,
         flimflam]
    v 1: deprive of by deceit; "He swindled me out of my
         inheritance"; "She defrauded the customers who trusted
         her"; "the cashier gypped me when he gave me too little
         change" [syn: victimize, swindle, rook, goldbrick,
         nobble, diddle, bunco, defraud, scam, mulct,
         gyp, gip, hornswoggle, short-change, con]