If you give or show someone the “cold shoulder,” this means that you shun them, ignore them, or treat them unkindly or unsympathetically. It’s an expression that apparently dates back over 200 years, with both the Oxford English Dictionary and Merriam-Webster tracing its earliest recorded use to 1816, when it appeared in The Antiquary, a novel by the Scottish writer Sir Walter Scott.
The Origins of “Cold Shoulder”

Given that there is no written record of the phrase before Scott’s use of it—and given that Scott is well known for coining his own phrases and expressions—it’s at least possible that he invented this one too. (It has even been suggested that he might have had a Bible verse in mind when he did so, and is somehow alluding to the Book of Nehemiah here).
Whether that’s the case, or whether Scott was simply repeating an expression he had heard locally in his writing, is all but impossible to say. But either way, his writing certainly worked to popularize the phrase.
The idea of the “cold shoulder” soon slipped into wider use in 19th-century English, and was promptly picked up by a handful of other contemporary novelists—including Charles Dickens, William Makepeace Thackeray, Anthony Trollope, and the Brontë sisters. It has remained in regular use language ever since.
Is the Phrase “Cold Shoulder” Referring to Meat?

But whose shoulder is the phrase “cold shoulder” referring to, and why is it cold? Well, there’s a fun theory that claims the shoulder in question here may be a portion of shoulder meat served, quite literally, cold.
How the phrase came to imply indifference or a lack of sympathy, this theory claims, is that an unwanted houseguest or uninvited visitor at dinnertime might be intentionally served cold meat by their host as a means of not-too-subtly signaling that the guest’s arrival wasn’t particularly welcome.
This theory became so ingrained and well-circulated, in fact, that particularly in the late 19th century, the phrase was often linked to meat and frequently appeared in contexts along the lines of “giving someone a cold shoulder of mutton.”
Even the OED has noted in its definition that the fact that the proverbial cold shoulder is commonly associated with meat has “suggested many puns and allusive uses” over the years.
As popular as this explanation is, though, it seems unlikely to be true. The “cold shoulder of mutton” theory here seems to be an example of a folk etymology—that is, a popular and widely repeated tale purporting to explain the origin of a word or phrase that, in reality, has no real evidence behind it to back it up.
Instead, the most likely explanation here is probably the simplest: given that cold-shouldering implies figuratively turning your back on someone, the shoulder being alluded to here would be your own. So when you give someone a cold shoulder, you effectively turn your back on them and coldly ignore whatever trouble or issue they might be having.
