Source : Webster's Revised Unabridged Dictionary (1913)

Far \Far\, a. [{Farther}and {Farthest}are used as the compar.
   and superl. of far, although they are corruptions arising
   from confusion with further and furthest. See {Further}.]
   [OE. fer, feor, AS. feor; akin to OS. fer, D. ver, OHG.
   ferro, adv., G. fern, a., Icel. fjarri, Dan. fjirn, Sw.
   fjerran, adv., Goth. fa[=i]rra, adv., Gr. ????? beyond, Skr.
   paras, adv., far, and prob. to L. per through, and E. prefix
   for-, as in forgive, and also to fare. Cf. {Farther},
   {Farthest}.]
   1. Distant in any direction; not near; remote; mutually
      separated by a wide space or extent.

            They said, . . . We be come from a far country.
                                                  --Josh. ix. 6.

            The nations far and near contend in choice.
                                                  --Dryden.

   2. Remote from purpose; contrary to design or wishes; as, far
      be it from me to justify cruelty.

   3. Remote in affection or obedience; at a distance, morally
      or spiritually; t enmity with; alienated.

            They that are far from thee ahsll perish. --Ps.
                                                  lxxiii. 27.

   4. Widely different in nature or quality; opposite in
      character.

            He was far from ill looking, though he thought
            himself still farther.                --F. Anstey.

   5. The more distant of two; as, the far side (called also off
      side) of a horse, that is, the right side, or the one
      opposite to the rider when he mounts.

   Note: The distinction between the adjectival and adverbial
         use of far is sometimes not easily discriminated.

   {By far}, by much; by a great difference.

   {Far between}, with a long distance (of space or time)
      between; at long intervals. ``The examinations are few and
      far between.'' --Farrar.

Source : WordNet®

by far
     adv : by a considerable margin; "she was by far the smartest
           student"; "it was far and away the best meal he had
           ever eaten" [syn: {far and away}, {out and away}]