'double-cross' originates from English, formed from the words 'double' and 'cross', where 'double' meant 'two, twice' and 'cross' (as a verb) meant 'to thwart or betray'.

'double' itself comes into English via Old French 'double' (from Latin 'duplus'), and 'cross' comes via Old English from Latin 'crux' (meaning 'cross'); the compound 'double cross' emerged in early modern/modern English usage (notably in criminal and espionage contexts) and later became commonly written as the hyphenated 'double-cross'.

Initially a literal idea of 'crossing twice' or 'turning against' someone, it came to mean specifically an act of treachery or deception in which someone is betrayed after being trusted.