rad·​i·​cal | \ ˈra-di-kəl How to pronounce radical (audio) \

Definition of radical

 (Entry 1 of 2)

1 : of, relating to, or proceeding from a root: such as
a(1) : of or growing from the root of a plant radical tubers
(2) : growing from the base of a stem, from a rootlike stem, or from a stem that does not rise above the ground radical leaves
b : of, relating to, or constituting a linguistic root
c : of or relating to a mathematical root
d : designed to remove the root of a disease or all diseased and potentially diseased tissue radical surgery radical mastectomy
2 : of or relating to the origin : fundamental
3a : very different from the usual or traditional : extreme
b : favoring extreme changes in existing views, habits, conditions, or institutions
c : associated with political views, practices, and policies of extreme change
d : advocating extreme measures to retain or restore a political state of affairs the radical right
4 slang : excellent, cool



Definition of radical (Entry 2 of 2)

1a : a root part
b : a basic principle : foundation
b : a sound or letter belonging to a radical
3 : one who is radical
4 : free radical also : a group of atoms bonded together that is considered an entity in various kinds of reactions or as a subunit of a larger molecule
5a : a mathematical expression indicating a root by means of a radical sign

Other Words from radical


radicalness noun

Examples of radical in a Sentence

Adjective The computer has introduced radical innovations. There are some radical differences between the two proposals. The new president has made some radical changes to the company. a radical wing of extremists Noun He was a radical when he was young, but now he's much more moderate. radicals staged large, violent protests in the hopes of toppling the government See More
Recent Examples on the Web: Adjective According to conspiracy theories circulating within far-left and radical Islamic circles, Israel eliminated the leadership of PIJ as an election stunt to advance the electoral chances of Prime Minister Yair Lapid in Israel's November election. Benjamin Weinthal, Fox News, 8 Aug. 2022 Zawahiri was shaped at a young age by Nasser’s crackdown on the Islamist movement, including the execution of Sayyid Qutb, a leading and radical member of the Muslim Brotherhood in 1966. Jared Malsin, WSJ, 2 Aug. 2022 Jason Wallach is charged with creating new psychedelics, engineered to deliver consistent, optimized, and potentially radical results. Wired, 28 July 2022 It’s trippy, radical, weirdly life-affirming music, like nothing else Greer has ever made. Simon Vozick-levinson, Rolling Stone, 26 July 2022 Do any parallels exist, or is this an entirely new and radical idea from the new mayor? cleveland, 23 July 2022 While often appearing benevolent–but always radical–Advance lurches towards authoritarianism, sparking the rise of the resistance group Disrupt. Matt Gardner, Forbes, 15 July 2022 To me, the pageant rhetoric commemorating Pride’s brave and radical beginnings always seemed so comically at odds with the fact that most Pride-goers appeared to be just… shirtless and wasted out-of-towners. Kyle Casey Chu, Vogue, 1 July 2022 Just watching Sam explore with an honest and radical sense of self. New York Times, 28 June 2022 Recent Examples on the Web: Noun At some point these articles must have come to the attention of Georg Büchner, a German medical student, playwright and political radical. Sam Sacks, WSJ, 24 June 2022 Failure to do so could bring a radical to the Presidency in five years—with damaging consequences far beyond France. The Editorial Board, WSJ, 20 June 2022 But right then, in that moment, the 40-something poet, journalist and simmering social radical was trapped in a luxury car with the corporate squares, a beetle in cooling agate. Dwain Hebda, Arkansas Online, 5 June 2022 Identity politics aside, Republicans will face two challenges in portraying Jackson as a wild-eyed radical. Dan Mclaughlin, National Review, 3 Mar. 2022 Opa chafed in particular at the books and articles that reinforced the Nazi claim that Arthur had been a political radical. Mattie Kahn, The Atlantic, 5 May 2022 The Left is busy convincing itself that Youngkin has morphed into a radical. The Editors, National Review, 19 Jan. 2022 However, critics have painted her as a dangerous radical, recalling Zelaya's closeness to late Venezuelan president Hugo Chavez. Reuters, CNN, 29 Nov. 2021 Thus, according to Biden, Sen. Mitt Romney is alternately an honorable man who will never break his word, or a dangerous radical who will put a predominantly African-American audience back in chains. W. James Antle Iii, The Week, 23 July 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radical.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of radical


14th century, in the meaning defined at sense 1


1641, in the meaning defined at sense 1a

History and Etymology for radical


Middle English, from Late Latin radicalis, from Latin radic-, radix root — more at root

Learn More About radical

Time Traveler for radical

Time Traveler

The first known use of radical was in the 14th century

See more words from the same century

Dictionary Entries Near radical



radical axis

See More Nearby Entries 

Statistics for radical

Last Updated

11 Aug 2022

Cite this Entry

“Radical.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radical. Accessed 13 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for radical


rad·​i·​cal | \ ˈra-di-kəl How to pronounce radical (audio) \

Kids Definition of radical

 (Entry 1 of 2)

1 : very new and different from the usual or ordinary : extreme a radical change
2 : of or relating to people who favor rapid and sweeping changes in laws and government

Other Words from radical

radically adverb



Kids Definition of radical (Entry 2 of 2)

: a person who favors rapid and sweeping changes especially in laws and government


rad·​i·​cal | \ ˈrad-i-kəl How to pronounce radical (audio) \

Medical Definition of radical

 (Entry 1 of 2)

1 : designed to remove the root of a disease or all diseased tissue radical surgery
2 : involving complete removal of an organ radical prostatectomy — compare conservative

Other Words from radical

radically \ -​i-​k(ə-​)lē How to pronounce radical (audio) \ adverb



Medical Definition of radical (Entry 2 of 2)

: free radical also : a group of atoms bonded together that is considered an entity in various kinds of reactions

More from Merriam-Webster on radical

Nglish: Translation of radical for Spanish Speakers

Britannica English: Translation of radical for Arabic Speakers

Britannica.com: Encyclopedia article about radical


Test Your Vocabulary

The Great British Vocabulary Quiz

  • union jack speech bubble
  • Named after Sir Robert Peel, what are British police called?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!