Simple Definition of tantamount
: equal to something in value, meaning, or effect
Full Definition of tantamount
: equivalent in value, significance, or effect <a relationship tantamount to marriage>
Examples of tantamount in a sentence
His statement was tantamount to an admission of guilt.
They see any criticism of the President as tantamount to treason.
Did You Know?
Tantamount comes from the Anglo-French phrase tant amunter, meaning "to amount to as much." This phrase comes from the Old French tant, meaning "so much" or "as much," and amounter, meaning "to ascend" or "to add up to." When tantamount first entered English, it was used similarly to the Anglo-French phrase, as a verb meaning "to be equivalent." "His not denying tant-amounteth to the affirming of the matter," wrote clergyman Thomas Fuller in 1659, for example. There was also a noun tantamount in the 17th century, but the adjective is the only commonly used form of the term nowadays.
Origin of tantamount
obsolete tantamount, noun, equivalent, from Anglo-French tant amunter to amount to as much
First Known Use: 1641
Seen and Heard
What made you want to look up tantamount? Please tell us where you read or heard it (including the quote, if possible).