WordNet (r) 3.0 (2006):

gamesmanship
    n 1: the use of dubious (although not technically illegal)
         methods to win a game

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "gamesmanship":
   Italian hand, acuteness, art, artfulness, artifice, astuteness,
   cageyness, callidity, canniness, cleverness, competition, craft,
   craftiness, cunning, cunningness, cutthroat competition, emulation,
   fine Italian hand, finesse, foxiness, guile, ingeniousness,
   insidiousness, inventiveness, jockeying, lifemanship,
   one-upmanship, readiness, resourcefulness, rivalry,
   satanic cunning, sharpness, shiftiness, shrewdness, slipperiness,
   slyness, sneakiness, sophistry, stealth, stealthiness, subtilty,
   subtleness, subtlety, suppleness, trickiness, vying, wariness,
   wiles, wiliness, wit