Translation guide
The English word "radical" has several distinct meanings. This guide helps learners choose the right Japanese expression depending on whether they mean extreme change, fundamental nature, a political extremist, a kanji component, or something excellent (slang).
Describing a change, reform, or idea that is thorough, drastic, or goes to the root of something.
A common adjective meaning 'drastic' or 'fundamental', often used with reform, review, or improvement.
Radical reform is necessary.
Means 'radical' in the sense of advocating rapid, sweeping change, often in politics or ideology.
He proposed radical policies.
Means 'thorough' or 'radical' in the sense of doing something completely, leaving no stone unturned.
We carried out a radical review.
Means 'extreme' or 'radical', often with a negative connotation of being too extreme or violent.
His radical remarks caused a problem.
Referring to the root, essence, or fundamental nature of something.
A person who supports radical political or social change.
The semantic component of a Chinese character used for dictionary lookup.
The standard term for a kanji radical. Use this when talking about kanji classification.
What is the radical of this kanji?
Informal way to say something is awesome, excellent, or extreme in a positive sense.
A very common word meaning 'the best' or 'awesome'. Not a direct translation of 'radical' but conveys the same enthusiastic approval.
That movie was radical!
Slang meaning 'amazing' or 'insane' (in a good way). Very casual, used by younger people.
Older slang (from 80s/90s) meaning 'cool' or 'stylish'. Similar vintage to English 'radical'.
The radical sign (√) or the root of a number.
An atom or molecule with an unpaired electron.
When using 'radical' as slang (meaning 'awesome'), do not directly translate it as 急進的 or 過激. Those words have political/extreme connotations. Instead, use 最高 or ヤバい for a natural, positive expression.
抜本的 is used for reforms, changes, or improvements that are drastic and thorough. 根本的 is used for causes, problems, or solutions that are fundamental or go to the root. While they overlap, 抜本的 implies action and change, while 根本的 implies essence and basis.
We need a radical solution to this problem.
He holds radical views on education.
This is a radical problem.
Radicals carried out a terrorist attack.
Isn't this song radical?
That jacket is radical.
The square root of 2 is an irrational number.
ラジカル重合について研究している。
I'm researching radical polymerization.