Faithless (8)
I believe the answer is:
disloyal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">faithless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for disloyal that I've seen before include "Violating trust" , "Not faithful, treacherous" , "Traitorous, unfaithful" , "Deserting one's allegiance" , "Unfaithful or unpatriotic" .)