The phrase "double cross" is often associated with betrayal or deception. An alternative synonym could be "betrayal" or "treachery." Other similar terms could be "backstabbing" or "two-timing." A person who double crosses someone could also be called a "traitor" or "sellout." Another phrase that can be used instead of double cross is "stab in the back." These synonyms can be used in a variety of situations, from personal relationships to political situations. No matter the context, these terms all convey a sense of betrayal and lack of trust.