Source : Webster's Revised Unabridged Dictionary (1913)

Fundamentally \Fun`da*men"tal*ly\, adv.
   Primarily; originally; essentially; radically; at the
   foundation; in origin or constituents. ``Fundamentally
   defective.'' --Burke.

Source : WordNet®

fundamentally
     adv : at bottom or by one's (or its) very nature; "He is basically
           dishonest"; "the argument was essentially a technical
           one"; "for all his bluster he is in essence a shy
           person" [syn: {basically}, {essentially}, {in essence},
            {au fond}]