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 Connecticut, assault is defined under several statutes that categorize the crime based on the severity of the injury, the intent of the perpetrator, and the status of the victim. For example, Connecticut General Statutes Section 53a-59 outlines Assault in the First Degree, which occurs when a person, with intent to cause serious physical injury to another person, causes such injury to such person or to a third person, or when a person with intent to disfigure or destroy another person's body part or organ does so, among other scenarios. Lesser degrees of assault, such as Assault in the Second and Third Degrees, are defined in Sections 53a-60 and 53a-61, respectively, and involve varying degrees of intent and harm. Assault in Connecticut does not require physical contact; the attempt or threat with the apparent ability to cause harm can constitute assault. The state also recognizes specific forms of assault, such as Assault on Public Safety or Emergency Medical Personnel (Section 53a-167c). Penalties for assault convictions vary widely depending on the degree of the assault and range from misdemeanors to felonies with substantial prison time.