Source : Webster's Revised Unabridged Dictionary (1913)

Intolerable \In*tol"er*a*ble\, a. [F. intol['e]rable, L.
   intolerabilis. See {In-} not, and {Tolerable}.]
   1. Not tolerable; not capable of being borne or endured; not
      proper or right to be allowed; insufferable;
      insupportable; unbearable; as, intolerable pain;
      intolerable heat or cold; an intolerable burden.

Source : WordNet®

intolerable
     adj 1: impossible to tolerate or endure; "an intolerable degree of
            sentimentality" [ant: {tolerable}]
     2: completely unacceptable; "this noise is intolerable"