HOCUS, a shortened form of " hpcus pocus," used in the 1yth century in the sense of " to play a trick on any one," to "hoax," which is generally taken to be a derivative. " Hocus pocus " appears to have been a mock Latin expression first used as the name of a juggler or conjurer. Thus in Ady's Candle in the Dark (jfiss), quoted in the New English Dictionary, " I will speak of one man . . . that went about in King James his time . . . who called himself, The Kings Majesties most excellent Hocus Pocus, and so was called, because that at the playing of every Trick, he used to say, Hocus pocus, tontus talontus, vade celeriter jubeo, a dark composure of words, to blinde the eyes of the beholders, to make his Trick pass the more currantly without discovery." Tillotson's guess (Sermons, xxvi.) that the phrase was a corruption of hoc est corpus and alluded to the words of the Eucharist, " in ridiculous imitation of the priests of the Church of Rome in their trick of Transubstantiation," has frequently been accepted as a serious derivation, but has no foundation. A connexion with a supposed demon of Scandinavian mythology, called " OchusBochus," isequally unwarranted. " Hocus " is used as a verb, meaning to drug, stupefy with opium, etc., for a criminal purpose. This use dates from the beginning of the 19th century.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)