1. Referring to a health effect, usually of rapid onset, brief, not prolonged; sometimes loosely used to mean severe.
2. Referring to exposure, brief, intense, short-term; sometimes specifically referring to brief exposure of high intensity.
The information shown above for acute is provided by Stedman's.
* Stedman's, part of Lippincott Williams & Wilkins, provide a comprehensive line of health-science publications for healthcare professionals and medical students.