radical

[ rad-i-kuhl ]

adjective

1. of or going to the root or origin; fundamental:

   There is a radical difference between the two interpretations of the sacred text, one justifying war and the other requiring nonviolent resistance.

   Synonyms: ingrained, innate, original, essential, basic

   Antonyms: superficial

2. extreme, especially as regards change from accepted or traditional forms:

   a radical change in the policy of the company.

   Synonyms: violent, immoderate, excessive, drastic, thorough, unqualified, complete

   Antonyms: superficial

3. favoring drastic political, economic, or social reforms:

   radical ideas;

   radical and anarchistic ideologues.

4. favoring, supporting, or representing extreme forms of religious fundamentalism:

   radical fundamentalists and their rejection of modern science.

5. forming a basis or foundation:

   What is the radical reason for his choice?

6. existing inherently in a thing or person:

   radical defects of character.

7. characterized by a marked departure from prevailing methods, practices, or ideas, particularly in the arts; experimental; unorthodox:

   The composer’s radical approach to sound, using timbre and rhythm rather than pitch, was declared “noise” by an influential critic.

8. Slang. excellent; wonderful; cool; rad:

   You got here on an electric skateboard? That's radical!

9. Mathematics.
   1. pertaining to or forming a root.
   2. denoting or pertaining to the radical sign.
   3. irrational ( def 5b ).
10. Grammar. of or pertaining to the root of a word.
11. Botany. of or arising from the root or the base of the stem.

noun

1. a person who holds or follows strong convictions or extreme principles; extremist.
2. a person who advocates fundamental political, economic, and social reforms by direct and often uncompromising methods.
3. Mathematics.
   1. a quantity expressed as a root of another quantity.
   2. the set of elements of a ring, some power of which is contained in a given ideal.
   3. radical sign ( def ).
4. Chemistry.
   1. group ( def 3 ).
   2. free radical ( def ).
5. Grammar. root ¹( def 12 ).
6. (in Chinese writing) one of 214 ideographic elements used in combination with phonetics to form thousands of different characters.

radical

/ ˈrædɪkəl /

adjective

1. of, relating to, or characteristic of the basic or inherent constitution of a person or thing; fundamental

   a radical fault

2. concerned with or tending to concentrate on fundamental aspects of a matter; searching or thoroughgoing

   radical thought

   a radical re-examination

3. favouring or tending to produce extreme or fundamental changes in political, economic, or social conditions, institutions, habits of mind, etc

   a radical party

4. med (of treatment) aimed at removing the source of a disease

   radical surgery

5. slang.
   very good; excellent
6. of, relating to, or arising from the root or the base of the stem of a plant

   radical leaves

7. maths of, relating to, or containing roots of numbers or quantities
8. linguistics of or relating to the root of a word

noun

1. a person who favours extreme or fundamental change in existing institutions or in political, social, or economic conditions
2. maths a root of a number or quantity, such as ³√5, √ x
3. Alsoradicle chem
   1. short for free radical
   2. another name for group
4. linguistics another word for root 1
5. (in logographic writing systems such as that used for Chinese) a part of a character conveying lexical meaning

radical

/ răd′ĭ-kəl /

1. A root, such as √2, especially as indicated by a radical sign (√).
2. A group of atoms that behaves as a unit in chemical reactions and is often not stable except as part of a molecule. The hydroxyl, ethyl, and phenyl radicals are examples. Radicals are unchanged by chemical reactions.

radical

¹

1. In chemistry , an atom or group of atoms that has at least one electron free to participate in forming a chemical bond .

radical

²

1. In politics, someone who demands substantial or extreme changes in the existing system.

Notes

In general, radicals are associated with chemical reactions that proceed rapidly.

Derived Forms

• ˈradicalness, noun

Other Words From

• rad·i·cal·i·ty [rad-i-, kal, -i-tee], rad·i·cal·ness noun
• mul·ti·rad·i·cal adjective
• non·rad·i·cal adjective noun
• qua·si-rad·i·cal adjective
• sem·i·rad·i·cal adjective
• sub·rad·i·cal adjective
• su·per·rad·i·cal adjective
• ul·tra·rad·i·cal adjective noun
• un·rad·i·cal adjective

Word History and Origins

Origin of radical¹

First recorded in 1350–1400; Middle English, from Late Latin rādīcālis “having roots, forming roots,” from Latin rādīc- (stem of rādix “root”) + -ālis -al ¹; root ¹

Word History and Origins

Origin of radical¹

C14: from Late Latin rādīcālis having roots, from Latin rādix a root

Synonym Study

Radical, extreme, fanatical denote that which goes beyond moderation or even to excess in opinion, belief, action, etc. Radical emphasizes the idea of going to the root of a matter, and this often seems immoderate in its thoroughness or completeness: radical ideas; radical changes or reforms. Extreme applies to excessively biased ideas, intemperate conduct, or repressive legislation: to use extreme measures. Fanatical is applied to a person who, especially in matters of religion or morality, has extravagant views and excessive zeal, rendering that person incapable of sound judgments and prone to take violent action against those who have differing views: fanatical in persecuting others.

Example Sentences

Old friends who never seemed to care about politics now seem ready to rain blows on those who disagree with their radical views.

From Washington Post

We asked them to lay out the steps for this radical classroom transformation.

From Popular-Science

An idea born in a Swiss patent office that evolved into a mature theory in Berlin set forth a radical new picture of the cosmos, rooted in a new, deeper understanding of gravity.

From Science News

The anxiety and loss of community some Q believers may feel can make them more vulnerable to believing radical ideas.

From FiveThirtyEight

Developing radical new technology is inherently risky, but that doesn’t make breaking this news any easier.

From Ars Technica

But Brooke was out of step with the New Left and its notion of radical chic.

From The Daily Beast

Too moderate and the more radical groups call you a snitch, jeopardizing your standing and authority at demonstrations.

From The Daily Beast

He has become the most radical pope in modern memory for his economic populism.

From The Daily Beast

He branded it a fifth-column invasion into popular culture, normalizing radical, even communist ambitions.

From The Daily Beast

Two hostages are dead and 15 others free after an Islamic radical took them hostage before police killed him.

From The Daily Beast

This letter indirectly points out two long-standing radical errors in engineering phraseology.

From Project Gutenberg

Decandolle's observations regarding the radical excretions of plants have not been confirmed by subsequent observers.

From Project Gutenberg

But if this reincarnation was quite ordinary in its process, it was the more radical and decisive.

From Project Gutenberg

There are two radical differences between Humanism and Christianity.

From Project Gutenberg

If the Collier were a Radical, how coal-black the portraits would come out!

From Project Gutenberg

Related Words

• agitator
• anarchist
• extremist
• fanatic
• firebrand
• insurgent
• leftist
• militant
• progressive
• rebel
• reformer
• renegade
• revolutionary
• rioter
• subversive