Synonyms of radical in English:

radical


See US English definition of radical

See UK English definition of radical

See Spanish definition of radical

adjective

1‘radical reform is long overdue’

SYNONYMS
thoroughgoing, thorough, complete, total, entire, absolute, utter, comprehensive, exhaustive, root-and-branch, sweeping, far-reaching, wide-ranging, extensive, profound, drastic, severe, serious, major, desperate, stringent, violent, forceful, rigorous, draconian
ANTONYMS

superficial

2‘the apparently radical differences between logic and natural language’

SYNONYMS
fundamental, basic, essential, quintessential
inherent, innate, structural, deep-seated, intrinsic, organic, constitutive, root
ANTONYMS

minor

3‘a radical political movement’

SYNONYMS
revolutionary, progressive, reforming, reformist, revisionist, progressivist
leftist, left-wing, ultra-left, socialist, anti-capitalist
extreme, extremist, fanatical, militant, diehard
informal red
British informal swivel-eyed
derogatory Bolshevik
ANTONYMS

conservative, reactionary, moderate


noun

1‘he was by no means a radical’

SYNONYMS
revolutionary, progressive, reformer, revisionist
leftist, left-winger, socialist
militant, zealot, extremist, fanatic, diehard
informal ultra, red
derogatory Bolshevik, Bolshevist
ANTONYMS

conservative, reactionary, moderate