The crime of assault varies from state to state (and under federal law), but is generally defined as intentionally putting another person in reasonable apprehension or fear of an imminent (immediate) harmful or offensive contact. The crime of assault may be committed even if there is no physical contact, as the criminal physical contact constitutes the separate crime of battery. In many states assaulting a police officer or peace officer who is performing official duties (such as making a lawful arrest) is a more serious offense—sometimes a felony.

In Hawaii, assault is defined under Hawaii Revised Statutes Section 707-710 to 707-713. Assault in Hawaii is generally categorized into three degrees. First-degree assault is the most serious, involving serious bodily injury or the use of a dangerous instrument, and is classified as a Class B felony. Second-degree assault involves substantial bodily injury, or recklessness and a dangerous instrument, and is a Class C felony. Third-degree assault is a misdemeanor and includes knowingly or recklessly causing bodily injury to another person or negligently causing bodily injury with a dangerous instrument. Assaulting a law enforcement officer, including a police officer or peace officer, while they are performing their duties is considered a separate offense under Section 707-712.5 and is a Class C felony. This reflects the state's stance on protecting officers in the line of duty, recognizing the offense as more serious compared to assault against a regular person.