Yahoo! Messenger, sometimes referred to as "Yahoo! Chat," allows individual or room-based chatting over the Internet. One feature of the Messenger program is a contact list in which you maintain a list of friends with whom you can chat. If you no longer with to chat with one of your contacts, you can choose to delete the contact from the list. However, that person can still contact you, unless you choose to "ignore" them as well.
Run Yahoo! Messenger as normal and look through your contact list for the contact you wish to delete.
Right-click that contact and select "Delete."
Click "Yes" to confirm deletion of the contact. If you would also like to remove that person from your Yahoo! account contact list as well, click to place a check mark by the option to remove the contact from Messenger and Yahoo! Contacts.
Place the contact on your "Ignore List." If you no longer wish to receive messages from them, you can do this by clicking "Preferences," "Privacy" and then the "Ignore List" tab. Click the "+" icon at the bottom and enter the contact ID to stop receiving messages from that person.