Source : Webster's Revised Unabridged Dictionary (1913)

Diplomatically \Dip`lo*mat"ic*al*ly\, adv.
   According to the rules of diplomacy; in the manner of a
   diplomatist; artfully.

Source : WordNet®

diplomatically
     adv : in a diplomatic manner; "he answered very diplomatically"
           [syn: {with diplomacy}] [ant: {undiplomatically}]