How to Delete an Invite from the Gmail Chat List
Google's online email service, Gmail, contains a list of chat invitations that occur when a contact has been invited to a chat with you. These chat invitations may sit unanswered for an indefinite amount of time if the user you sent the request to does not respond. Your chat list can quickly become overwhelmed with these unanswered requests. Gmail only removes these invitations when the contact has been deleted from your address book.
Log into Gmail at the gmail.com website.
Place a check mark next to the name of the contact who has an unanswered pending chat invitation.
Click "Delete Contact" and confirm the action when prompted. The chat invitation no longer appears on your account.