What does Deadstock mean in Vintage Clothing?

Now a days you will see many different variations in descriptions for Vintage Clothing and accessories.One of the most gemon term used is "Deadstock". This means that the seller is stating the item has never been used or worn. How is the buyer/bidder to actually know this to be true. If in fact this is deadstock the original tags will be on the garment and or in its original packages. Happy Collecting!