What it means: ‘The cold shoulder’ is when you intentionally but somewhat passively act unfriendly towards someone.

Where it comes from: The first comes from medieval England when everyone was done feasting, the host would give guests a cold piece of meat from the shoulder as a way of asking them to leave. The second is if a less-desirable guest showed up at a residence, the host would not prepare a hot meal but instead give a cold piece of meat.