"Biastophilia" (or "raptophilia", also "paraphilic rape") is referred to as paraphilia in which sexual arousal is dependent on, or is responsive to, the act of assaulting an unconsenting person, especially a stranger.
Some dictionaries consider the terms synonymous, while others distinguish raptophilia as the paraphilia in which sexual arousal is responsive to actually raping the victim.
The source of the arousal in these paraphilias is the terrified resistance to the assasult, and in this respect it is considered to be a form of sexual sadism.
Biastophilia can be potentially lethal; other such paraphilias include, but are not limited to, asphyxiophilia, autassassinophilia, hybristophilia and chremastistophilia.
Under the name Paraphilic Coercive Disorder, this diagnosis has been proposed for inclusion in DSM-5. This diagnosis, under the name Paraphilic Rapism, was proposed - and rejected - in DSM-III-R, and has been criticized because of the impossiblility of reliably distinguishing between paraphilic rape and non-paraphilic rape, and because of the way that this diagnosis, under the term paraphilia NOS (not otherwise specified): nonconsent has been used in Sexually Violent Person/Predator commitment.
Czech sexology standardly uses a concept of "pathologic sexual aggressivity" instead. This term is strongly distinguished from sadism. This disorder is understand as a coordination anomaly of the sexual motivation system (SMS), a "courtship disorder" according of Kurt Freund, or displacement paraphilia by John Money, or missing segment of SMS.