Source : Webster's Revised Unabridged Dictionary (1913)

Tolerable \Tol"er*a*ble\, a. [L. tolerabilis: cf. F.
   tol['e]rable. See {Tolerate}.]
   1. Capable of being borne or endured; supportable, either
      physically or mentally.

            As may affect the earth with cold and heat Scarce
            tolerable.                            --Milton.

   2. Moderately good or agreeable; not contemptible; not very
      excellent or pleasing, but such as can be borne or
      received without disgust, resentment, or opposition;
      passable; as, a tolerable administration; a tolerable
      entertainment; a tolerable translation. --Dryden. --
      {Tol"er*a*ble*ness}, n. -- {Tol"er*a*bly}, adv.

Source : WordNet®

tolerable
     adj 1: able to be tolerated or endured; "the climate is at least
            tolerable" [ant: {intolerable}]
     2: neither good nor bad; "an indifferent performance"; "a
        gifted painter but an indifferent actor"; "her work at the
        office is passable"; "a so-so golfer"; "feeling only
        so-so"; "prepared a tolerable dinner"; "a tolerable
        working knowledge of French" [syn: {indifferent}, {passable},
         {so-so(p)}]