Source : Webster's Revised Unabridged Dictionary (1913)

Foully \Foul"ly\, v.
   In a foul manner; filthily; nastily; shamefully; unfairly;
   dishonorably.

         I foully wronged him; do forgive me, do. --Gay.

Source : WordNet®

foully
     adv 1: in an unfair and insulting manner; "this internationally
            known writer was foully condemned by the Muslim
            fundamentalists" [syn: {insultingly}]
     2: in a wicked and shameful manner; "two policemen were foully
        murdered"