Oversight is a form of enhanced deletion, which, unlike normal deletion, expunges and suppresses the deleted material from administrators and bureaucrats. Admins and bureaucrats can usually view and restore deleted content, but they cannot do such with content that has been deleted with oversight.
Additionally, oversight can be used to hide a username that is grossly inappropriate from Special:ListUsers at the same time as indefinitely blocking them. This feature will also suppress the username from most logs and edits, although the username may still be visible in some places, such as rollback edit summaries.
Because of the sensitive nature of the tool, oversight is only available to stewards and system administrators. Oversight should only be used to remove personal information, copyright infringement, serious personal attacks, or other grossly insulting material. Except in these cases, standard admin deletion should be used.