According to About.com, the crime of assault may be charged for any conduct, physical or otherwise, that is intended to put the victim in fear of bodily harm. While swearing at someone is not typically regarded as a form of assault, threats of violence certainly are and can be prosecuted.
LegalMatch cites numerous scenarios in which assault may be charged without physical violence having occurred. The guiding legal principle is whether or not the victim suffered physical or mental injury as a result of the assailant's actions. While even direct threats might not be charged under the assault statutes, any combination of words with other factors, such as wielding a weapon, that induces a fear of immediate harm can amount to the felony charge of assault.
According to LegalMatch, assault can even be charged when the perpetrator acted without criminal malice. Sometimes an assault charge can result from a poorly planned or executed practical joke if the result involved harm to another person. A person may be made the victim of assault even if it is possible to safely flee the area where the assault took place. This is because the assault is considered to have occurred the moment an immediate threat is perceived.