To permanently delete your account, go to the Privacy Settings tab, located under settings in the drop down and click on the "Disable Account" button.
Note: once this has been done, there is no way for you to reactivate your account.
Please choose a reason for disabling your account. This helps us continue to buld the best possible product.
Remember, once you Disable your account, you will not be able to come back to it.
Your account may still appear in a Google search until Google reindexes their search. The timing of this is determined by Google. To learn more about Google's removable of outdated content and how to request a removal of outdated content, click here: https://support.google.com/websearch/answer/6349986?hl=en