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Definitions

radical

[rad-i-kuhl] / ˈræd ɪ kəl /
ADJECTIVE
fundamental, basic
Synonyms
STRONGEST
profound
STRONG
basal bottom cardinal constitutional essential native natural organic original primary primitive
WEAK
deep-seated foundational inherent innate intrinsic meat-and-potatoes primal thoroughgoing underlying vital
Antonyms
STRONG
inessential minor secondary unimportant
WEAK
extrinsic nonessential superficial
ADJECTIVE
deviating by extremes
Synonyms
STRONGEST
extremist fanatical far-out leftist militant progressive revolutionary sweeping uncompromising violent
STRONG
entire freethinking insurgent recusant refractory
WEAK
advanced anarchistic complete excessive iconoclastic immoderate insubordinate insurrectionary intransigent lawless mutinous nihilistic rabid rebellious recalcitrant restive riotous seditious severe thorough ultra ultraist way-out
Antonyms
STRONGEST
moderate
WEAK
conservative superficial
NOUN
person who advocates significant, often extreme change
Synonyms
STRONGEST
agitator anarchist extremist fanatic firebrand insurgent leftist militant progressive rebel reformer renegade revolutionary rioter subversive
STRONG
avant-garde freethinker iconoclast insurrectionist left-winger mutineer nihilist nonconformist objector pacifist secessionist
WEAK
revolter ultraist
Antonyms
WEAK
conservative moderate

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

What on earth had driven them to become so radical?

From Slate • May 4, 2026

"Our work shows that even radical ideas about quantum mechanics can be tested against precise physical measurements, and that, reassuringly, timekeeping remains one of the most stable pillars of modern physics."

From Science Daily • May 3, 2026

Speaking to the BBC, Syth said the operator had shied away from the radical overhaul it needed during a 2024 bankruptcy procedure.

From BBC • May 2, 2026

A few years ago, I pitched my boss, the chief marketing officer, on a radical idea to merge the call center with my social-media department.

From The Wall Street Journal • Apr. 30, 2026

In October 1917 the radical Bolshevik Party took advantage of people’s anger over World War I and overthrew the Provisional Government.

From "A Thousand Sisters" by Elizabeth Wein

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