rad·i·cal
ˈra-di-kəl 
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
3
a
: 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
radicalness
noun
1
a
: a root part
b
: a basic principle : foundation
2
a
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
5
a
: a mathematical expression indicating a root by means of a radical sign
b
Synonyms
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
Recent Examples on the Web
Sarah E. Parkinson, Foreign Affairs, 11 Nov. 2024
This makes Godot feel like a free-flowing, creative instrument users share and improve together as a radical hacker collective.
—PCMAG, 7 Nov. 2024
Sharon Coolidge, The Enquirer, 27 Oct. 2024
Selenium can prevent oxidative damage in the body, fight off radicals, and improve cell function.14 Selenium deficiencies have been linked to thyroid problems, decreased immune system function, hormonal imbalance, mood disorders, and heart disease.
7.
—Lana Barhum, Verywell Health, 31 Oct. 2024
See all Example Sentences for radical 
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Adjective
Assassinations can also elevate more radical or more effective leaders.
—Sarah E. Parkinson, Foreign Affairs, 11 Nov. 2024
This makes Godot feel like a free-flowing, creative instrument users share and improve together as a radical hacker collective.
—PCMAG, 7 Nov. 2024
Noun
My opponent also aligns herself with political radicals who view the justice system as a means to help and serve criminals, as opposed to victims of crime and our community.
—Sharon Coolidge, The Enquirer, 27 Oct. 2024
Selenium can prevent oxidative damage in the body, fight off radicals, and improve cell function.14 Selenium deficiencies have been linked to thyroid problems, decreased immune system function, hormonal imbalance, mood disorders, and heart disease.
7.
—Lana Barhum, Verywell Health, 31 Oct. 2024
See all Example Sentences for radical
Dictionary Entries Near radical
Cite this Entry
“Radical.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radical. Accessed 22 Nov. 2024.
Copy CitationKids Definition
radical
1 of 2 adjective
rad·i·cal
ˈrad-i-kəl
1
: of, relating to, or proceeding from a root
2
a
: departing sharply from the usual or ordinary : extreme
b
: of or relating to radicals in politics
radically
adverb
-k(ə-)lē
radicalness
noun
radical
2 of 2 noun2
: a person who favors rapid and sweeping changes especially in laws and methods of government
3
: a group of atoms bonded together that is considered as a unit in various kinds of reactions
4
a
: a mathematical expression (as √͞ x) involving a radical sign
b
Etymology
Adjective
Middle English radical "relating to a root," from Latin radicalis (same meaning), from earlier radic-, radix "root" — related to eradicate, radish
Word Origin
Our word radical was formed from the Latin adjective radicalis, which simply meant "of or relating to a root." The Latin word radix meant "root." This meaning was kept when the word radicalis came into English as radical, but new senses developed too. Since a root is at the bottom of something, radical came to describe what is at the base or beginning, in other words, what is "basic, fundamental." Later, radical was used to describe something that was extremely different from the usual. Then, as a noun radical came to be applied to a person who wants to make extreme or "radical" changes in the government or in society. In mathematics, a radical sign indicates a root of a number. The words radish and eradicate also come from the Latin radix.
Medical Definition
radical
1 of 2 adjective
rad·i·cal
ˈrad-i-kəl
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
radical
2 of 2 noun
: free radical
also
: a group of atoms bonded together that is considered an entity in various kinds of reactions
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