In discussing the ambivalence of emotions in his work on "Totem and Taboo", Freud has pointed out that the word Taboo had a double meaning, namely, holy and unclean. An interesting example of a slip of the tongue revealing this ambivalence of a subject so generally "tabooed" in modern life, namely, sexual intercourse, is the following:

During the course of an analysis I was discussing with the patient, aged 36, his juvenile attitude toward intercourse, when he remarked that he did not wish to indulge, because "intercourse is sacred" and thereupon he immediately corrected himself saying, "No, I mean intercourse is secret". In the investigation which followed it developed that the patient had associated with the idea of intercourse both the qualities of holiness (sacred), (holy bond of matrimony), and secret (something to be hidden, something not nice, something unclean). The slip of the tongue not only revealed the suppressed meaning but indicated the conscious association, the combination of which formed the classical primal attributes of Taboo.