radical >> /ˈrædək(ə)l/
Definition: [noun] A person who advocates thorough or complete political or social reform; a member of a political party or part of a party pursuing such aims.
Example: The party has not tried to disguise its new deregulatory approach, which is causing unease among party radicals.
Definition: [noun] A group of atoms behaving as a unit in a number of compounds.
Example: Examples of compounds or groups that accept anions include the nitrate and hydroxide radicals.
Definition: [noun] The root or base form of a word.
Definition: [noun] A quantity forming or expressed as the root of another.
Example: In 1845 Wantzel, continuing his researches into equations, gave a new proof of the impossibility of solving all algebraic equations by radicals.
Definition: [adjective] (especially of change or action) relating to or affecting the fundamental nature of something; far-reaching or thorough.
Example: a radical overhaul of the existing regulatory framework
Definition: [adjective] Advocating or based on thorough or complete political or social change; representing or supporting an extreme or progressive section of a political party.
Example: a radical American activist
Definition: [adjective] Denoting or relating to the roots of a word.
Definition: [adjective] Of the root of a number or quantity.
Definition: [adjective] Of, or springing direct from, the root or stem base of a plant.
Definition: [adjective] Very good; excellent.