(arising from or going to the root or source) radical
(of or relating to or constituting a linguistic root) radical
(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; radical
substantiv
((chemistry) two or more atoms bound together as a single unit and forming part of a molecule) group; chemical group; radical
(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) free radical; radical
(a person who has radical ideas or opinions) radical
((mathematics) a quantity expressed as the root of another quantity) radical
(a character conveying the lexical meaning of a logogram) radical