来自短语 tant amount,等同，一致，来自拉丁语 tantus,一样的，一致，来自 tam,因此，所以， 词源同 tandem,this,that.主要用于贬义修饰。
英文词源
tantamount
tantamount: [17] Tantamount means etymologically ‘amounting to as much’. It comes from an earlier verb tantamount ‘amount to as much as, be equal to’, which was a lexicalization of the Anglo-Norman expression tant amunter ‘amount to as much’. This was made up of tant ‘as much’, which came via Old French from Latin tantus, and amunter, ancestor of English amount. => amount, paramount
tantamount (adj.)
1640s, from verbal phrase tant amount "be equivalent" (1620s), from Anglo-French tant amunter "amount to as much" (late 13c.), from Old French tant "as much" (11c., from Latin tantus, from tam "so;" see tandem) + amonter "amount to, go up" (see amount (v.)).
双语例句
1. What Bracey is saying is tantamount to heresy.
布雷西的言论简直就是异端邪说。
来自柯林斯例句
2. If he resigned it would be tantamount to admitting that he was guilty.
他若辞职就等于承认自己有错。
来自《权威词典》
3. This invasion is tantamount to a declaration of war.
这次侵略就相当于宣战.
来自《简明英汉词典》
4. Her confession was simply tantamount to a casual explanation.
她的自白简直等于一篇即席说明.
来自《现代英汉综合大词典》
5. To neglect or forget aspects of the past is tantamount to rewriting history, and anyone who has read Animal Farm knows where that can lead.