Search Result for "perfidiously": 
Wordnet 3.0

ADVERB (1)

1. in a perfidious manner;
- Example: "he was playing perfidiously one side against the other"


The Collaborative International Dictionary of English v.0.48:

Perfidiously \Per*fid"i*ous*ly\, adv. In a perfidious manner. [1913 Webster]
WordNet (r) 3.0 (2006):

perfidiously adv 1: in a perfidious manner; "he was playing perfidiously one side against the other"