Source : Webster's Revised Unabridged Dictionary (1913)

Condescendingly \Con`de*scend"ing*ly\, adv.
   In a condescending manner. --Atterbury.

Source : WordNet®

condescendingly
     adv : with condescension; in a patronizing manner; "he treats his
           secretary condescendingly" [syn: {patronizingly}, {patronisingly}]