All users are given the option to deactivate their account at any given time.
DeviantART Deactivated Account

DeviantART Deactivated Account screenshot, with a crying Fella.

The deactivated account's name appears as crossed out, similar to when a Deviant has been banned. Originally, deviantART users had to send a request to Staff to have their accounts Deactivated, and in the process the Staff would ban the original accounts rather than use a Deactivation feature. To this day, many Deviants who originally wanted their account to be Deactivated have the "banned" symbol over their page, but deviantART may or may not have intended threat reports on their website available.

Deviantart new deactivated page

A new deactivated page in DeviantArt, with confused Fella with folders.

In a new update, DeviantArt's deactivated account image was changed into a confused Fella with folders, same goes for the Not Found error.

When the account is deactivated, you are given the chance to reactivate it two days after deactivation, but this lasts only for a month. When this limit is exceeded, the account will be permanently deleted from DeviantArt and all content associated with the account will be erased completely.