Of the 16 definitions of CROSS (as a verb) in the Meriam-Webster dictionary (US), here is #5, with its five sub-meanings. The one used in DOUBLE-CROSS is 5.c(2), “to turn against” (synonym BETRAY) ______________________________ CROSS (verb) 5. a(1) : to run counter to : OPPOSE a(2) : to deny the validity of : CONTRADICT b : to confront in a troublesome manner : OBSTRUCT c(1) : to spoil completely : DISRUPT c(2) : to turn against : BETRAY ______________________________ If you think of the noun CROSS, the idea of “turning against” is evident. ✖️

我做了一些研究，发现在 1700 年代，“cross”是一种不公平和不诚实的交易。 （例如，如果推销员向您出售了有缺陷的商品。） 如果您改变方向并从您来的方向返回，我们使用短语"to double back”。 因此，单词组合演变为意味着某人已经改变方向并且现在以某种方式欺骗您。 = to double-cross For example: "My business partner double-crossed me. He made a secret deal to sell the company without talking to me." Good luck!