Pass around refers to the act of sharing or distributing something among a group of people. Some antonyms for pass around include hoard, keep to oneself, withhold, retain, and store. The opposite of passing something around would be to keep it to oneself, not share it with others, or hold onto it. In some situations, keeping something to oneself might be desirable, such as with personal belongings or confidential information. In other cases, withholding or hoarding something could be seen as selfish, and passing around or distributing items might be more appropriate. Ultimately, the choice of action depends on the context and the nature of what is being passed around.