Faithlessly
The Century Dictionary and Cyclopedia
In a faithless manner.
Wiktionary, Creative Commons Attribution/Share-Alike License
adverb.
In a
faithless
manner
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adverb.
in a disloyal and faithless manner
Word Usage
"The President is elected to faithfully execute the laws, and not faithlessly try to work around them."