The Collaborative International Dictionary of English v.0.48:

outfox \out*fox"\ (out`f[o^]ks") v. t. [out + fox; from the
   supposed cleverness of a fox in stalking prey.]
   To defeat or gain an advantage over (an antagonist) by clever
   stratagems; to outwit; to outmaneuver; to outsmart.
   [PJC]

WordNet (r) 3.0 (2006):

outfox
    v 1: outdo someone in trickery
    2: beat through cleverness and wit; "I beat the traffic"; "She
       outfoxed her competitors" [syn: outwit, overreach,
       outsmart, outfox, beat, circumvent]