RADICAL definition: of or going to the root or origin; fundamental. See examples of radical used in a sentence.

If something is considered extremist or very different from anything that has come before it, call it radical.

RADICAL definition: 1. believing or expressing the belief that there should be great or extreme social or political…. Learn more.

An individual atom or element as a constituent of a compound was formerly termed a simple radical, as distinct from a group or compound radical. The use of the word for single atoms is now unusual …

Relating to or advocating fundamental or revolutionary changes in current practices, conditions, or institutions: radical politics; a radical political theorist.

A radical is someone who has radical views. Vanessa and I had been student radicals together at Berkeley from 1965 to 1967.

Dec 18, 2025 · radical (comparative more radical, superlative most radical) Favoring fundamental change, or change at the root cause of a matter.