Final answer:
The patient with sudden abdominal symptoms, including rebound tenderness, is experiencing acute pain, which is short-term and severe in nature.
Step-by-step explanation:
The patient experiencing sudden right lower-quadrant pain, nausea, vomiting, and rebound tenderness should have their pain classified as acute pain. This type of pain usually comes on quickly and is caused by something specific. It is of short duration but often severe. The description provided does not match the definitions of chronic pain, which persists over a longer period, intractable pain, which is resistant to treatment, or neuropathic pain, which is pain caused by nerve damage.