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Line breaks: rad|ical
Pronunciation: /ˈradɪk(ə)l

Definition of radical in English:


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
More example sentences
  • Both groups would be affected by a radical change in the business climate.
  • Are the arguments of those who predict a radical change in the nature of 21st century wars that groundless after all?
  • The people are exhausted from the radical changes that affect their way of life.
thoroughgoing, thorough, complete, total, entire, absolute, utter, comprehensive, exhaustive, root-and-branch, sweeping, far-reaching, wide-ranging, extensive, profound, drastic, severe, serious, major, desperate, stringent, violent, forceful, rigorous, draconian
1.1Forming 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
More example sentences
  • He said yesterday: ‘Football results do not make a radical difference to society but they can have an impact.’
  • Note also the radical difference between how our culture defines ‘fashionable’ thinness for men and women.
  • As for the property rights of authors to their works, the consequences of these differences are radical.
1.2(Of surgery or medical treatment) thorough and intended to be completely curative.
Example sentences
  • The principal concern is that age bias will lead to the use of palliative therapies as opposed to curative treatments and radical surgical procedures in older adult patients.
  • More serious cancers, however, will require radical surgery, radiotherapy, and chemotherapy.
  • In patients who are unfit to have radical surgery, radiotherapy may be administered to the inguinal lymph nodes.
2Characterized by departure from tradition; innovative or progressive: the city is known for its radical approach to transport policy
More example sentences
  • Given the extent to which it is taken for granted today, it can be difficult to fully appreciate the truly innovative and radical approach Frege took to logic.
  • The resulting album attracted two nominations in the Radio 2 folk awards with its radical approach to traditional music.
  • She calls for a radical re-examination of traditional approaches to accountability, transparency and press freedom.
2.1Advocating 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
More example sentences
  • Wales has always had strong left wing and radical political parties and leaders.
  • She has been the most radical advocate of the party's adoption of an independent stance in elections.
  • Hard-liners formed a radical political party, more extremist than any other.
2.2British historical Belonging to an extreme section of the Liberal party during the 19th century.
Example sentences
  • He was elected as MP for Stirling Burghs in 1868, and gained a reputation as a radical Liberal.
3Relating to the root of something, in particular:
3.1 Mathematics Of the root of a number or quantity.
Example sentences
  • The answers are thirteen over four and two plus or minus radical seven.
3.2Denoting or relating to the roots of a word.
3.3 Music Belonging to the root of a chord.
3.4 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!


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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.
Example sentences
  • The party has not tried to disguise its new deregulatory approach, which is causing unease among party radicals and old-style social democrats.
  • I try to be a radical in political and social ways, but I'm a terrible conservative when it comes to technology.
  • Rohm was not really a social or political radical.
2 Chemistry A group of atoms behaving as a unit in a number of compounds. See also free radical.
Example sentences
  • Examples of compounds or groups that accept anions include the nitrate and hydroxide radicals.
  • Marcel Nicolet resolved some of this discrepancy by showing how reactive molecular fragments called radicals convert ozone molecules back into O 2.
  • Subsequent oxidation-reduction reactions can also produce superoxide anions, hydrogen peroxide and hydroxyl radicals.
3The root or base form of a word.
Example sentences
  • The word can refer to a geminate verb, i.e., a triliteral verb where the second and third radicals are the same - also called mediae geminatae.
3.1Any 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.
Example sentences
  • By learning the function of radicals of Chinese characters, students can learn new characters by groups and strings.
  • Finally, the Lexical Decision test is a measure of children's right-left spatial reversals of Chinese radicals.
  • There are about 200 radicals representing basic subjects.
4 Mathematics A quantity forming or expressed as the root of another.
Example sentences
  • In 1845 Wantzel, continuing his researches into equations, gave a new proof of the impossibility of solving all algebraic equations by radicals.
  • From its true emergence, algebra can be seen as a theory of equations solved by means of radicals, and of algebraic calculations on related expressions.
  • When the exponent is a prime number, I say that its radical cannot be divisible by any other prime except those that are greater by one than a multiple of double the exponent.
4.1A radical sign.


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



Example sentences
  • Labour's promised radicalism is set to focus on a new architecture for Britain's government.
  • There is certainly support for this view of Scottish radicalism from social attitude surveys in the last 30 years.
  • The story of Perry Anderson is the story of the British left and the revival of Marxism and radicalism after the Second World War.


[as submodifier]: a radically different approach
More example sentences
  • Algae, or silkweed as it is commonly known, deserves a radically different approach to that of lilies.
  • We're both in very different parts of the country, which can mean radically different weather.
  • Without realising it, we are learning a radically new set of linguistic rules.


Example sentences
  • He had become a Tendai Buddhist at this temple - imagine the radicalness of that in Victorian times!
  • The problem wasn't with their radicalness but their absurd level of self-importance.
  • It also stems from the thoroughness with which he examined Western philosophical traditions, especially from Kant onward, and the radicalness to his critique of contemporary Western society.

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