implacable

adjective

im·​pla·​ca·​ble (ˌ)im-ˈpla-kə-bəl  -ˈplā- 

: not placable : not capable of being appeased, significantly changed, or mitigated

an implacable enemy

implacability

(ˌ)im-ˌpla-kə-ˈbi-lə-tē 

-ˌplā-

noun

implacably

(ˌ)im-ˈpla-kə-blē 

-ˈplā-

adverb

Did you know?

Implacable is rooted in Latin placare, meaning "to soothe," but its im- prefix is a variant of the negating prefix in- (as in inactive) and it signals that there’s nothing warm and fuzzy here. Someone or something described as implacable cannot be soothed, which usually means trouble: implacable is most often attached to words like foe, enemy, hatred and hostility. The opposite of implacable is, of course, placable; it means "easily soothed," but sadly isn’t called upon very often. Another placare word is likely more familiar. Placate means "to soothe or appease"; it’s frequently applied when an angry person is made to feel less so.

Synonyms

• adamant
• adamantine
• bullheaded
• dogged
• hard
• hard-nosed
• hardened
• hardheaded
• headstrong
• immovable
• inconvincible
• inflexible
• intransigent
• mulish
• obdurate
• obstinate
• opinionated
• ossified
• pat
• pertinacious
• perverse
• pigheaded
• self-opinionated
• self-willed
• stiff-necked
• stubborn
• unbending
• uncompromising
• unrelenting
• unyielding
• willful
• wilful

Examples of implacable in a Sentence

He has an implacable hatred for his political opponents.

an implacable judge who knew in his bones that the cover-up extended to the highest levels of government

Recent Examples on the Web

In the past, news organizations have met governmental threats and incursions with implacable resistance. —Michael Wolff, The Hollywood Reporter, 13 Mar. 2025

Pius stands facing the camera in a white cassock, two fingers of his right hand raised in benediction, his gaze penetrating and implacable. —Cullen Murphy, airmail.news, 15 Feb. 2025

But on a personal level, what does the guy with all those titles think about the seemingly implacable force in Kansas City, and how might the prospect of watching Mahomes make history have an impact on Brady’s call? —Anthony Crupi, Sportico.com, 5 Feb. 2025

And with that, Noah made the implacable Rose start crying in front of friends and family, all 20,000 of them. —Jon Greenberg, The Athletic, 4 Jan. 2025

Word History

Etymology

Middle English, from Latin implacabilis, from in- + placabilis placable

First Known Use

15th century, in the meaning defined above

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Kids Definition

implacable

adjective

im·​pla·​ca·​ble (ˈ)im-ˈplak-ə-bəl  -ˈplā-kə- 

: not possible to please, satisfy, or change

an implacable enemy

implacability

-ˌplak-ə-ˈbil-ət-ē 

-ˌplā-kə-

noun

implacably

-ˈplak-ə-blē 

-ˈplā-kə-

adverb