Source : Webster's Revised Unabridged Dictionary (1913)

Privily \Priv"i*ly\, adv.
   In a privy manner; privately; secretly. --Chaucer. --2 Pet.
   ii. 1.

Source : WordNet®

privily
     adv : confidentially or in secret; "told her friend privily that
           she was planning to be married"