Explain aggravated assault please.
Aggravated assault is a serious offense and most States have recognized it as a felony. A key to the charge of aggravated assault is intent of the assailant. If the assailant acted with forethought and conviction, aggravated assault will stand on it's own merits. In most cases, an injury must be sustained by a victim. Intent cases are an assault with the added component of "assault with intent to rape", assault with intent to kill, or assault with a deadly weapon."
Assault with a deadly weapon is interesting because physical injury need not be suffered by the victim. A mere frightening of another while in posession of a deadly weapon will bring a charge of assault with a deadly weapon.
Criminal Law/Emanuel/p. 268
Aggravated assault may mean slightly different things from state to state, but normally it means someone has committed assault against another person with aggravating factors. For example, they used a gun, knife, or other deadly weapon in the assault, or they demonstrated a clear intent to kill, seriously injure or otherwise harm the victim with whatever was used in the assault.
In general, such a charge is used when the attack is more serious than a typical case, such as a barroom fight. So the prosecutors and the states consider such perpetrators to be more dangerous to society, so they created a more serious layer to the assault charge that carries a stiffer sentence.