1. [ adjective ] (used of opinions and actions) far beyond the norm
Synonyms: ultra extremist

"extremist political views" "radical opinions on education" "an ultra conservative"

Related terms: immoderate
2. [ noun ] (chemistry) two or more atoms bound together as a single unit and forming part of a molecule
Synonyms: group chemical_group
Related terms: substance unit methylene_group nitrate vinyl carboxyl cyano_group benzoyl_group hydroxyl uranyl alkyl allyl nitrite azo_group nitro_group acetyl azido_group glyceryl cacodyl propyl Butyl hydrazo_group ketone_group acyl alcohol_group aldehyde_group chromophore amino_group carbonyl_group benzyl molecule chemistry
3. [ adjective ] (politics) markedly new or introducing radical change
Synonyms: revolutionary

"a revolutionary discovery" "radical political views"

Related terms: new
4. [ noun ] (chemistry,physics) 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
Synonyms: free_radical

"in the body free radicals damage cells"

Related terms: atom
5. [ noun ] (politics) a person who has radical ideas or opinions
Related terms: person disputant anarchist Bolshevik terrorist trot Young_Turk revolutionist leveler wobbly extremist
6. [ adjective ] arising from or going to the root
Synonyms: root

"a radical flaw in the plan"

Related terms: basic
7. [ adjective ] (linguistics) of or relating to or constituting a linguistic root

"a radical verb form"

Related terms: linguistics root
8. [ noun ] (mathematics) a sign placed in front of an expression to denote that a root is to be extracted
Synonyms: radical_sign
Related terms: mathematical_notation
9. [ adjective ] (botany) 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
Synonyms: basal

"basal placentation" "radical leaves"

Related terms: cauline botany
10. [ noun ] (linguistics) a character conveying the lexical meaning of a logogram
Related terms: character ideogram
11. [ noun ] (linguistics) the form of a word after all affixes are removed
Synonyms: stem root theme base root_word

"thematic vowels are part of the stem"

Related terms: form linguistics
Similar spelling:   radically