One form of verbal obscenity is the habitual use of language with excretory and uro-genitary references, or the frequent utterance of coarse expressions relating to sexual acts. Medically this is termed coprotatia or coprophasia. Its perverted objectives may be to elicit sexual responses, or to attain exhibitionistic auto-erotic excitation. Involuntary coprotatia, as an automatism, may accompany some forms of psychoses in both sexes, but may also be produced under persistent or extreme stress. Traditionally, coprotatia was viewed as a sign of demonic possession. A second group of swear words refer to other parts of the body. A third group are unacceptable because they are considered blasphemous. Many swear words transform over time and enter a more acceptable, even innocuous category : the 1914-18 war destroyed the strength of "bloody" as a swear word. There is also more generosity to users of swear words in moments of anger, passion or frustration, when the word is not intended in its literal meaning. Context appears to be critical in determining borderline cases.
Investigations by the Broadcasting Standards Council of the UK, found that in 1991 that the following words were considered acceptable on television by more than 50% of people: blast, damn, bloody, sod, hell, bugger, bleeding, dipstick, shit, crap, pillock, god, bullshit, christ, jesus, balls, god almighty, dickhead, fart, bonk, bastard, turd, tits, twat and piss. "Fuck" was found to be at the boundary of significance, as compared with words like "cunt", which the vast majority believed should not be used on television. In a study published in 1994 the Council found that in an average week 54% of programmes contained bad language, with 3,323 incidents, at a rate of 10.6 per hour. The highest percentage was found in films with 17.1 incidents per hour. In the period 1992-93, incidence of bad language increased from 6.9 incidents per hour to 7.6 per hour.