Dictionary.com
Thesaurus.com
Synonyms

implacable

American  
[im-plak-uh-buhl, -pley-kuh-] / ɪmˈplæk ə bəl, -ˈpleɪ kə- /

adjective

  1. not to be appeased, mollified, or pacified; inexorable.

    an implacable enemy.

    Synonyms:
    merciless, unbending, unappeasable

implacable British  
/ ɪmˈplækəbəl /

adjective

  1. incapable of being placated or pacified; unappeasable

  2. inflexible; intractable

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See inflexible.

Other Word Forms

Etymology

Origin of implacable

First recorded in 1375–1425; late Middle English word from Latin word implācābilis. See im- 2, placable

Explanation

An implacable person just can’t be appeased. If you really offended your best friend and tried every kind of apology but she refused to speak to you again, you could describe her as implacable. Implacable is derived from the verb to placate, which means to soothe, or to appease. If you’re babysitting and the kid starts screaming the moment that his parents leave the house, and nothing you give him, be it a toy or ice cream, can calm him down, he might seem implacable. But try the TV. It tends to turn screaming kids into silent, happy zombies.

Keep Reading on Vocabulary.com

Vocabulary lists containing implacable

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.

Supreme Court historically used Asian Americans’ supposedly implacable foreignness to justify greater, institutionally enforced apartness.

From Slate • May 26, 2026

Lee Marvin plays an implacable man out for vengeance in this 1967 thriller, arriving in a 4K restoration, that keeps the audience at a cool remove.

From The Wall Street Journal • Apr. 15, 2026

I felt sickened by every piece of news I gave her—her court date canceled, the border closed, the pandemic spreading—but her faith in the system, and in me, seemed implacable.

From Slate • Jan. 15, 2026

García Harfuch — always decked out in suit and tie — transmits an aura of competence, and his media-savvy advisors have burnished his image as an implacable foe of the cartels.

From Los Angeles Times • Nov. 29, 2025

It is a great story now of implacable vengeance and tragic passions and inevitable doom.

From "Mythology: Timeless Tales of Gods and Heroes" by Edith Hamilton

Vocabulary.com logo
by dictionary.com

Look it up. Learn it forever.

Remember "implacable" for good with VocabTrainer. Expand your vocabulary effortlessly with personalized learning tools that adapt to your goals.

Take me to Vocabulary.com