Perfidiously
The Century Dictionary and Cyclopedia
In a perfidious manner; with perfidy; treacherously; traitorously.
the GNU version of the Collaborative International Dictionary of English
adverb.
In a perfidious manner.
Wiktionary, Creative Commons Attribution/Share-Alike License
adverb.
In a
perfidious
manner.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adverb.
in a perfidious manner
Word Usage
"The Baron could, by a single word perfidiously repeated, injure him very much with Alba's mother."