Radical

(used of opinions and actions) far beyond the norm

markedly new or introducing radical change

especially of leaves; located at the base of a plant or stem; especially arising directly from the root or rootstock or a root-like stem

arising from or going to the root or source

of or relating to or constituting a linguistic root

an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule that has lost an electron and will stabilize itself by stealing an electron from a nearby molecule

(linguistics) the form of a word after all affixes are removed

(chemistry) two or more atoms bound together as a single unit and forming part of a molecule

a character conveying the lexical meaning of a logogram

a person who has radical ideas or opinions

(mathematics) a quantity expressed as the root of another quantity