im·​pla·​ca·​ble (ˌ)im-ˈpla-kə-bəl How to pronounce implacable (audio) -ˈplā- How to pronounce implacable (audio)
: not placable : not capable of being appeased, significantly changed, or mitigated
an implacable enemy
implacability noun
implacably 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.

Example Sentences

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 face of an opaque, implacable adversary, strategists in Washington are keen to avoid a prolonged war. Ishaan Tharoor, Washington Post, 17 Feb. 2023 Should China become an implacable aggressor, however, the Pentagon does have war plans in place to attack China’s defensive bubble. Anna Mulrine Grobe, The Christian Science Monitor, 9 Feb. 2023 Moehringer, at least, knows this, even if Harry may hope that his own royal plot will swerve unexpectedly from implacable tragedy to restitutive melodrama. Rebecca Mead, The New Yorker, 13 Jan. 2023 But the old life of pressing olives and herding sheep is faltering in the face of an implacable drought. Vivian Yee, New York Times, 19 Jan. 2023 The newspaper’s circulation soon plummeted over its implacable opposition to the war. Daniel Akst, WSJ, 7 Dec. 2022 And northerly countries such as Iceland have begun to hold funerals for glaciers felled by the planet’s implacable heat. Katherine J. Wu, The Atlantic, 19 Dec. 2022 The public will often reach the same calculus, coming to see their attacker as an implacable threat that can only be neutralized through defeat. Max Fisher, New York Times, 11 Oct. 2022 As the Iranian revolution transformed the region, the shock of suddenly facing an implacable enemy instilled in the Saudis a visceral fear of popular uprisings—either within their own kingdom or in any neighboring country. Kim Ghattas, The Atlantic, 24 Nov. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'implacable.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


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

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of implacable was in the 15th century


Dictionary Entries Near implacable

Cite this Entry

“Implacable.” Dictionary, Merriam-Webster, Accessed 23 Mar. 2023.

Kids Definition


im·​pla·​ca·​ble (ˈ)im-ˈplak-ə-bəl How to pronounce implacable (audio) -ˈplā-kə- How to pronounce implacable (audio)
: not possible to please, satisfy, or change
an implacable enemy
implacability noun
-ˈplak-ə-blē How to pronounce implacable (audio)

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