Source : Webster's Revised Unabridged Dictionary (1913)

Definitely \Def"i*nite*ly\, adv.
   In a definite manner; with precision; precisely;
   determinately.

Source : WordNet®

definitely
     adv : without question and beyond doubt; "it was decidedly too
           expensive"; "she told him off in spades"; "by all odds
           they should win" [syn: {decidedly}, {unquestionably}, {emphatically},
            {in spades}, {by all odds}]