What is the origin, or at least first use, of the phrase "the knives are out for…?"
Definition from Merriam-Webster:
used to say that people are ready to blame or punish someone for something often in a way that is unfair. "They lost yet another important game, and now the knives are out for their coach."
Best Answer
Both "the knives are out for X" and the closely allied "Y have there knives out for X" go back more than a century—to no later than 1895 and 1889, respectively.
An early instance of "Y have their knives out for X" appears in "Prophets of Evil," in the Omaha [Nebraska] Daily Bee (February 19, 1889):
Harrison was the Republican candidate for U.S. president in 1888, and won the election over the incumbent Democratic president, Grover Cleveland. At the time of this news article, Harrison was still about two weeks away from taking office (which he did on March 4, 1889). Four years later, Harrison was defeated in his bid for reelection by ... Grover Cleveland.
The expressions "have their knives out for [someone]" and "the knives are out for [someone]" may call to mind the assassination of Julius Caesar. Consistent with that reading, the wording in the excerpt above, "prophecies of trouble awaiting [the new administration]," might suggest the famous warning in Shakespeare's Julius Caesar, "Beware the ides of March."
Figurative use of "Y have their knives out for X" seems to have caught on fairly rapidly in the 1890s. It also appears in unrelated newspaper articles in Pittsburgh, Pennsylvania (October 15, 1891), Shenandoah, Pennsylvania (October 31, 1891), Fort Worth, Texas (February 28, 1893, in an instance that specifies "scalping knives"), New York City (May 30, 1895, with scalping again specified), Salt Lake City, Utah (October 17, 1895), and Omaha, Nebraska (May 25, 1896).
The earliest Elephind match for the wording "knives are out for X" appears in an untitled item in the [Montpelier] Vermont Watchman & State Journal (October 2, 1895):
Tammany Hall was a notoriously powerful and corrupt political club that ran New York City politics in the late 1800s. Its symbol was a tiger.
The sense of "knives are out for X" in this excerpt is not fundamentally different from the sense of "Y have their knives out for X" in the earlier instances.