extreme

Concise Oxford English Dictionary © 2008 Oxford University Press:
extreme/ɪkˈstriːm/

▶adjective

• 1 very great.

  ■ not usual; exceptional.

  ■ very severe or serious.

  ■ denoting or relating to a sport performed in a hazardous environment.

• 2 far from moderate, especially politically.

• 3 furthest from the centre or a given point.

▶noun

• 1 either of two things that are as different from each other as possible.

  ■ the most extreme degree: extremes of temperature.

• 2 Logic the subject or predicate in a proposition, or the major or minor term in a syllogism.

– derivatives
extremely adverb,
extremeness noun.

– origin ME: via OFr. from L. extremus ‘outermost, utmost’, superlative of exterus ‘outer’.