Important: If you use Google Chat and not classic Hangouts, visit block and report someone.
People who don’t know you need to send an invitation to send messages. To protect you, classic Hangouts filters spam invitations from your regular view. If a spam invitation isn't filtered or if you don't feel comfortable in a Hangout with someone, you can block them. When you block someone, they can tell if you’re online but can't send you classic Hangouts messages.
Tip: If strangers or spammers contact you, you can choose who can contact you directly.
Classic Hangouts is being replaced by Google Chat for everyone. You are no longer able to use classic Hangouts on most platforms. Learn about the switch from classic Hangouts to Google Chat.