Source : Webster's Revised Unabridged Dictionary (1913)

Immeasurably \Im*meas"ur*a*bly\, adv.
   In an immeasurable manner or degree. ``Immeasurably
   distant.'' --Wordsworth.

Source : WordNet®

immeasurably
     adv 1: to an immeasurable degree; beyond measurement; "the war left
            him immeasurably fearful of what man can do to man"
            [ant: {measurably}]
     2: without bounds; "he is infinitely wealthy" [syn: {boundlessly},
         {infinitely}]