Extreme  —adj. 1 of a high, or the highest, degree (extreme danger). 2 severe (extreme measures). 3 outermost. 4 on the far left or right of a political party. 5 utmost; last. —n. 1 (often in pl.) Either of two things as remote or as different as possible. 2 thing at either end. 3 highest degree. 4 math. First or last term of a ratio or series.  go to extremes take an extreme course of action. In the extreme to an extreme degree.  extremely adv. [french from latin]