What is the origin of the idiom "cold shoulder" and when to use it?

The origin of the idiom "cold shoulder" is uncertain, but there are a few theories about its origin. One theory suggests that it comes from the custom of serving a cold shoulder of meat to an unwelcome guest as a sign of rejection or disinterest. Another theory links it to the practice of turning one's shoulder coldly toward someone to show indifference or lack of interest. Regardless, this expression is now used to describe situations where someone is intentionally being distant or unfriendly towards another person.