Serving to disappoint or deceive
Not true to allegiance, duty, or vows
Lacking faith; lacking belief in something.
Unfaithful (said of people, towards their partners)
Not believing in God, religion, or a comparable ideology.
Not observant of promises or covenants.
Quick to change one’s opinion or allegiance; insincere; not loyal or reliable.
Changeable.
To puzzle, perplex, nonplus.
To deceive, flatter.