It's a way of ostracizing someone, refusing to speak to them, or interact with them in any way.
Origin:
The idiom's origin is uncertain, but it's thought to be linked to the city of Coventry in England. There are a few possible explanations:
* The Siege of Coventry (1642-46): During the English Civil War, Royalist prisoners of war were held in Coventry and treated poorly by the Parliamentarian forces. This might have led to the phrase, as prisoners were essentially ignored and left alone.
* Coventry's textile industry: Coventry was known for its wool and cloth trade, and weavers who produced substandard work were often punished by being sent to a special "Coventry loom" where they were forced to work alone and produce inferior quality fabric.
Example:
"After the argument, everyone sent him to Coventry, refusing to speak to him or acknowledge his presence."