To send someone to Coventry is a British idiom meaning to deliberately ostracise someone. Typically, this is done by not talking to them, avoiding someone's company and generally pretending that they no longer exist. Victims are treated as though they are completely invisible and inaudible. It is often used to punish people who, for example, refuse to join a strike. The Coventry referred to in the phrase is a cathedral city in the West Midlands, England.