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O tempora! O mores!

American  
[oh tem-poh-rah oh moh-reys, oh tem-per-uh oh mawr-eez, mohr-] / oʊ ˈtɛm poʊˌrɑ oʊ ˈmoʊ reɪs, oʊ ˈtɛm pər ə oʊ ˈmɔr iz, ˈmoʊr- /
Latin.

  1. O times! O customs!

O tempora! O mores! British  
/ əʊ ˈtɛmpɔːrɑː əʊ ˈmɔːreɪz /

  1. oh the times! oh the customs!: an exclamation at the evil of them

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of O tempora! O mores!

from Cicero's oration In Catilinam

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.