Source : Webster's Revised Unabridged Dictionary (1913)

Unbiased \Un*bi"ased\, a. [Pref. un- + biased.]
   Free from bias or prejudice; unprejudiced; impartial. --
   {Un*bi"ased*ness}, n.

Source : WordNet®

unbiased
     adj 1: characterized by a lack of partiality; "a properly
            indifferent jury"; "an unbiased account of her family
            problems" [syn: {indifferent}, {unbiassed}]
     2: without bias [syn: {unbiassed}]