Source : Webster's Revised Unabridged Dictionary (1913)

Decidedly \De*cid"ed*ly\, adv.
   In a decided manner; indisputably; clearly; thoroughly.

Source : WordNet®

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