Due to the fact that you do not need to provide any personal information, and Wiktionary/Wikipedia needs to track who made what changes, the site is not on the black list.
Nevertheless, if you still fear your privacy: you cannot delete your account – only change your login. See http://en.wikipedia.org/wiki/Wikipedia:FAQ#How_do_I_change_my_username.2Fdelete_my_account.3F
URLS:
http://wiktionary.org