radical

 
Pronunciation: /ˈradɪk(ə)l/

adjective

  • 1(especially of change or action) relating to or affecting the fundamental nature of something; far-reaching or thorough: a radical overhaul of the existing regulatory framework
  • forming an inherent or fundamental part of the nature of someone or something: the assumption of radical differences between the mental attributes of literate and non-literate peoples
  • (of surgery or medical treatment) thorough and intended to be completely curative.
  • 2characterized by departure from tradition; innovative or progressive: the city is known for its radical approach to transport policy
  • advocating or based on thorough or complete political or social reform; representing or supporting an extreme or progressive section of a political party: a radical American activist
  • British historical belonging to an extreme section of the Liberal party during the 19th century.
  • 3relating to the root of something, in particular:
  • Mathematics of the root of a number or quantity.
  • denoting or relating to the roots of a word.
  • Music belonging to the root of a chord.
  • Botany of, or springing direct from, the root or stem base of a plant.
  • 4 [usually as exclamation] North American informal very good; excellent: Okay, then. Seven o’clock. Radical!

noun

  • 1a person who advocates thorough or complete political or social reform; a member of a political party or part of a party pursuing such aims.
  • 2 Chemistry a group of atoms behaving as a unit in a number of compounds. See also free radical.
  • 3the root or base form of a word.
  • any of the basic set of approximately 214 Chinese characters constituting semantically or functionally significant elements in the composition of other characters and used as a means of classifying characters in dictionaries.
  • 4 Mathematics a quantity forming or expressed as the root of another.
  • a radical sign.

Derivatives

radicalism

noun

radically

adverb
[as submodifier]: a radically different approach

radicalness

noun

Origin:

late Middle English (in the senses 'forming the root' and 'inherent'): from late Latin radicalis, from Latin radix, radic- 'root'