Source : Webster's Revised Unabridged Dictionary (1913)

Outflank \Out*flank"\, v. t. (Mil.)
   To go beyond, or be superior to, on the flank; to pass around
   or turn the flank or flanks of.

Source : WordNet®

outflank
     v 1: go around the flank of (an opposing army) [syn: {go around}]
     2: get the better of; "the goal was to best the competition"
        [syn: {outdo}, {trump}, {best}, {scoop}]