Source : Webster's Revised Unabridged Dictionary (1913)

Icily \I"ci*ly\, adv.
   In an icy manner; coldly.

         Faultily faultless, icily regular, splendidly null,
         Dead perfection, no more.                --Tennyson.

Source : WordNet®

icily
     adv : in a cold and icy manner; "`Mr. Powell finds it easier to
           take it out of mothers, children and sick people than
           to take on this vast industry,' Mr Brown commented
           icily"