radical

US /ˈrædɪkəl,'rædɪkḷ/

UK /ˈrædɪkl/

B1
n. (c./u.)Noun (Countable/Uncountable)Person who believes in extreme political change
He is a radical, who thinks war is the only answer
adj.AdjectiveVery new and different from what is traditional
I love his radical ideas, they are so interesting and refreshing
adj.AdjectiveConcerning something's most basic part or form
We need a radical change if we hope to end this job on time
n. (c./u.)Noun (Countable/Uncountable)A group of atoms behaving as a unit in a chemical compound.
A methyl group is a simple example of a radical.
n. (c./u.)Noun (Countable/Uncountable)The root of a word.
The radical of the word 'running' is 'run'.
adj.AdjectiveAdvocating or based on thorough or complete political or social reform; representing or supporting an extreme section of a political party.
He has radical political views.
n. (c./u.)Noun (Countable/Uncountable)A quantity expressed as the root of another.
The radical sign indicates the root of a number.
n. (c./u.)Noun (Countable/Uncountable)An atom, molecule, or ion that has an unpaired electron and is therefore unstable and highly reactive.
Free radicals can damage cells.
n. (c./u.)Noun (Countable/Uncountable)In linguistics, a radical is a basic part of a character, especially in Chinese and other East Asian scripts.
The radical Ct is a component of many Chinese characters.

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