資料來源 : pyDict

不忠地;背信地

資料來源 : Webster's Revised Unabridged Dictionary (1913)

Perfidiously \Per*fid"i*ous*ly\, adv.
   In a perfidious manner.

資料來源 : WordNet®

perfidiously
     adv : in a perfidious manner; "he was playing perfidiously one
           side against the other"