Expelliarmus

Martha Jones used the word "Expelliarmus" in an improvised verse against the Carrionites in 1599, after William Shakespeare was unable to come up with a suitable rhyme. (TV: The Shakespeare Code)

Behind the scenes
Expelliarmus is the incantation for the Disarming Charm in the Harry Potter universe, a spell used to disarm an opponent of their weapon, usually their wand.