faithless vs two-timing

faithless

• Unfaithful (said of people, towards their partners) 

• Not true to allegiance, duty, or vows 

• Lacking faith; lacking belief in something. 

• Not believing in God, religion, or a comparable ideology. 

• Serving to disappoint or deceive 

• Not observant of promises or covenants. 

two-timing

• Sexually or romantically unfaithful. 

• The practice of being sexually or romantically unfaithful.