greys

1. (UK, prison slang) Grey trousers and/or jackets worn by prisoners on relatively formal occasions.Examples: "There was a clatter at the back of the gallery, a sharp word from a warder, and the men marched in in their prison greys, jackets too large, trousers too small."; "'No one told me that I had to be dressed in Greys not Blues! When I appeared before the BOV I was told that I could not go in and see them because I was improperly dressed.'"; "“Drop your trousers!” I loosened the clasp on my prison greys and my trouser dropped to my ankles."UKpluralplural-onlyslang