To send someone to Coventry is a British idiom meaning to ostracise someone, usually by not talking to them. When we send someone to Coventry we avoid them intentionally or prevent them from taking part in the activities of a group. This is usually done as a form of punishment for having done something to upset the group.
Coventry in this idiom is a city in England. No one is sure why Coventry is linked to avoiding/not talking to someone; however, some think that during The English Civil Wars of the 1640s, prisoners of war were sent to Coventry, where they were ignored by the local people who did not want them there.
"His friends sent him to Coventry after they found out he had been lying to them."
"John was sent to Coventry by his family for not going to his sister's wedding."
Here's the idiom used by legendary record producer Brian Eno in an interview for Pitchfork Media
"When ABBA were around, to admit that you liked them would have condemned you to absolute Coventry. No one would talk to you because you liked ABBA, because they were considered to be hopelessly pointless pop. Now, of course, everyone likes ABBA."
Have you ever been sent to Coventry? What did you do about it?