Confundo

(from http://en.wikipedia.org/wiki/Spells_in_Harry_Potter#K)

Pronunciation: con-FUN-doh (IPA: /kʌn.ˈfʌn.dəʊ/)

Description: Causes the victim to become confused and befuddled. Seen/Mentioned: First mentioned in Harry Potter and the Prisoner of Azkaban,

when Severus Snape suggests that Harry and Hermione Granger had been Confunded to

believe Sirius Black's claim to innocence[PA Ch.21]. In Harry Potter and the

Goblet of Fire, it is suggested that a powerful Confundus Charm is responsible for

the Goblet choosing a fourth Triwizard contestant[GF Ch.17]. It is first seen in

action when Hermione uses it on Cormac McLaggen during Quidditch tryouts in Harry

Potter and the Half-Blood Prince[HBP Ch.11]. Its vernacular name is first revealed

when Harry uses it on security guards during the Gringotts break-in in Harry

Potter and the Deathly Hallows and Ron used it to pass a driving test in the

epilogue.

Suggested Etymology: The Latin word confundo which means, "to confuse, throw into disorder".[4]