The Collaborative International Dictionary of English v.0.48:

Far \Far\, a. [Fartherand Farthestare 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[imac]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.
      [1913 Webster]

            They said, . . . We be come from a far country.
                                                  --Josh. ix. 6.
      [1913 Webster]

            The nations far and near contend in choice.
                                                  --Dryden.
      [1913 Webster]

   2. Remote from purpose; contrary to design or wishes; as, far
      be it from me to justify cruelty.
      [1913 Webster]

   3. Remote in affection or obedience; at a distance, morally
      or spiritually; t enmity with; alienated.
      [1913 Webster]

            They that are far from thee ahsll perish. --Ps.
                                                  lxxiii. 27.
      [1913 Webster]

   4. Widely different in nature or quality; opposite in
      character.
      [1913 Webster]

            He was far from ill looking, though he thought
            himself still farther.                --F. Anstey.
      [1913 Webster]

   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.
      [1913 Webster]

   Note: The distinction between the adjectival and adverbial
         use of far is sometimes not easily discriminated.
         [1913 Webster]

   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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Farther \Far"ther\ (f[aum]r"[th][~e]r), a., compar. of Far.
   [superl. Farthest (-[th][e^]st). See Further.] [For
   farrer, OE. ferrer, compar. of far; confused with further.
   Cf. Farthest.]
   1. More remote; more distant than something else.
      [1913 Webster]

   2. Tending to a greater distance; beyond a certain point;
      additional; further.
      [1913 Webster]

            Before our farther way the fates allow. --Dryden.
      [1913 Webster]

            Let me add a farther Truth.           --Dryden.
      [1913 Webster]

            Some farther change awaits us.        --MIlton.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Farther \Far"ther\, adv.
   1. At or to a greater distance; more remotely; beyond; as,
      let us rest with what we have, without looking farther.
      [1913 Webster]

   2. Moreover; by way of progress in treating a subject; as,
      farther, let us consider the probable event.
      [1913 Webster]

   No farther, (used elliptically for) go no farther; say no
      more, etc.
      [1913 Webster]

            It will be dangerous to go on. No farther ! --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Farther \Far"ther\, v. t.
   To help onward. [R.] See Further.
   [1913 Webster]

WordNet (r) 3.0 (2006):

farther
    adv 1: to or at a greater extent or degree or a more advanced
           stage (`further' is used more often than `farther' in
           this abstract sense); "further complicated by uncertainty
           about the future"; "let's not discuss it further";
           "nothing could be further from the truth"; "they are
           further along in their research than we expected"; "the
           application of the law was extended farther"; "he is
           going no farther in his studies" [syn: further,
           farther]
    2: to or at a greater distance in time or space (`farther' is
       used more frequently than `further' in this physical sense);
       "farther north"; "moved farther away"; "farther down the
       corridor"; "the practice may go back still farther to the
       Druids"; "went only three miles further"; "further in the
       future" [syn: farther, further]
    adj 1: more distant in especially space or time; "they live in
           the farther house"
    2: more distant in especially degree; "nothing could be further
       from the truth"; "further from our expectations"; "farther
       from the truth"; "farther from our expectations" [syn:
       further, farther]