Source : Webster's Revised Unabridged Dictionary (1913)

Unfavorable \Un*fa"vor*a*ble\, a.
   Not favorable; not propitious; adverse; contrary;
   discouraging. -- {Un*fa"vor*a*ble*ness}, n. --
   {Un*fa"vor*a*bly}, adv.

Source : WordNet®

unfavorably
     adv : showing disapproval; in a disparaging way; "he reviewed the
           play unfavorably" [syn: {unfavourably}] [ant: {favorably}]