radical
gb/ɹˈædɪkəl/ us/ɹˈædɪkəl/
B1
English
~ 2600
Senses
0 senses
adjective
B2
property
1
Extreme or far from the usual
Very different from normal or traditional; extreme.
Usage pattern:
[someone/something] is radical
Common mistake:
Learners sometimes confuse 'radical' with 'rad', which is slang for 'cool' and not appropriate in formal contexts.
Synonyms
extreme (More general and can apply to degree or intensity without implying novelty or change.)
|
revolutionary (Suggests bringing about major change, often political or social.)
Antonyms
moderate (Implies avoiding extremes and preferring gradual change.)
Collocations
radical change
|radical reform
|radical idea
|radical approach
|radical solution
Themes
politics
|society
|change
|core_vocabulary
Examples
- The new leader proposed a radical change to the education system.
- Her views on environmental policy are considered radical by many.
- The company adopted a radical approach to solving the problem.
- He made a radical decision to quit his job and travel the world.
- This was a radical departure from their usual style.
Learner examples
- This is a radical idea.
- The city needs radical changes.
- She has radical plans for the school.
- He wants a radical new law.
- It was a radical move by the team.
Noun
B2
entity
2
Person with extreme views
A person who wants big changes in politics or society.
Usage pattern:
[someone] is a radical
Synonyms
extremist (Often more negative, can imply willingness to use force or violence.)
Antonyms
moderate (Supports gradual change rather than extreme measures.)
Collocations
political radical
|social radical
|left-wing radical
Themes
politics
|society
|relationships
Examples
- The radicals in the movement demanded immediate action.
- He was seen as a radical during his university days.
- Some radicals were arrested during the protest.
- The party's radicals opposed the compromise.
- She has been labeled a radical for her beliefs.
Learner examples
- He is a radical in politics.
- The group has many radicals.
- She is called a radical by her friends.
- Some radicals want fast change.
- Radicals often fight for new ideas.
adjective
informal
B1
property
3
Excellent or impressive (slang)
(Slang) Very good or cool.
Usage pattern:
[something] is radical
Common mistake:
Learners may use this slang in formal situations where it is inappropriate.
Synonyms
awesome (Very informal, similar casual tone.)
|
cool (Informal, common in youth speech.)
Antonyms
lame (Slang for boring or unimpressive.)
Collocations
radical design
|radical performance
Themes
slang
|youth_culture
|communication
|core_vocabulary
Examples
- That skateboard trick was totally radical!
- The concert last night was radical.
- Your new bike looks radical!
Learner examples
- The movie was radical.
- His car is radical.
- That game is radical.
Noun
technical
C1
entity
4
Group of atoms in chemistry
(Chemistry) A group of atoms that act together in reactions.
Collocations
free radical
Themes
science
|chemistry
Examples
- Free radicals can damage cells and lead to aging.
- A hydroxyl radical is highly reactive.
- Chemists study how radicals affect reactions.
Learner examples
- Free radicals can harm the body.
- A radical can change other molecules.
- Some radicals react very fast.
Noun
technical
B2
entity
5
Mathematical root symbol or value
(Math) The √ sign or the number under it that shows a root.
Collocations
square root radical
Themes
mathematics
|education
|science
Examples
- In √9, the radical sign indicates a square root.
- The expression under the radical is 16.
- Simplify the radical before solving the equation.
Learner examples
- The radical sign means root.
- We see a radical in this math problem.
- A radical can show a square root.
Grammar
Dictionary form
radical
IPA
GB/ɹˈædɪkəl/
US/ɹˈædɪkəl/
Syllables & stress
rad - ic - al (3 syllables)
Stress on 1st syllable (rad)
Word forms
Adjective
- Base: radical
Noun
- Base: radical
- Plural: radicals
Word family
Forms
radicals
noun
Core family
radically
adverb B2
Related words
radicalism
noun
Negative and opposite forms
moderate
adjective B1
Advanced or less common
radicalize
verb
radicalization
noun C1
Expressions
free radical
1/fɹˈi ɹˈædɪkəl/
fixed phrase
technical
Atom/molecule with unpaired electron
An atom or molecule that has an unpaired electron and can react easily.
Examples
- Free radicals can cause damage to cells.
- Antioxidants help neutralize free radicals.
radical change
1/ɹˈædɪkəl t͡ʃˈeɪnd͡ʒ/
fixed phrase
Major and complete transformation
A big and complete change.
Examples
- The country needs a radical change in its energy policy.
- Radical change is necessary to solve the crisis.
radical reform
1/ɹˈædɪkəl ɹɪfˈɔɹm/
fixed phrase
Thorough alteration of system/law
A big and complete change to laws or systems.
Examples
- The education system requires radical reform.
- Radical reform of the tax code is long overdue.