radical

(used of opinions and actions) far beyond the norm

• “extremist political views”
• “radical opinions on education”
• “an ultra conservative”

markedly new or introducing radical change

• “a revolutionary discovery”
• “radical political views”

arising from or going to the root

• “a radical flaw in the plan”

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

• “basal placentation”
• “radical leaves”

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

an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule than 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”

a person who has radical ideas or opinions

a character conveying the lexical meaning of a logogram

a sign placed in front of an expression to denote that a root is to be extracted

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

• “thematic vowels are part of the stem”