radical

(used of opinions and actions) far beyond the norm.

“radical opinions on education”

Of or relating to or constituting a linguistic root.

“a radical verb form”

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.

“radical leaves”

Markedly new or introducing radical change.

“radical political views”

Arising from or going to the root or source.

“a radical flaw in the plan”

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

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.

“in the body free radicals are high-energy particles that ricochet wildly and damage cells”

(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.