English
implacable
Implacable comes from Old French implacable ‘harsh, unrelenting’, from Latin implācābilis ‘unappeasable, implacable’, and ultimately from plācō ‘to assuage, pacify, placate’.
- Latinc. 75 BCE–200 CEplācō1‘to assuage, pacify, placate’
- Latinc. 75 BCE–200 CEplācābilis1‘placable’
- Latinc. 75 BCE–200 CEimplācābilis1‘unappeasable, implacable’
- Old Frenchc. 842–1400implacable1‘harsh, unrelenting’
- Middle Englishc. 1150–1500implācāble1‘immitigable, unappeasable’
- Englishearliest quotation c. 1601–1602implacable1
attested reconstructed ? uncertain or disputed deepest recorded ancestor
- 1 Wiktionary, English implacable
- Earliest quotation in Wiktionary’s entry: c. 1601–1602, William Shakespeare, Twelfe Night, or What You Will: “He is knight dubb'd with vnhatche'd Rapier, and on…”.
Earlier history uncertain. See Wiktionary.
Lineage
- Latinc. 75 BCE–200 CEplācōWiktionary, English implacable‘to assuage, pacify, placate’
- Latinc. 75 BCE–200 CEplācābilisWiktionary, English implacable‘placable’
- Latinc. 75 BCE–200 CEimplācābilisWiktionary, English implacable‘unappeasable, implacable’
- Old Frenchc. 842–1400implacableWiktionary, English implacable‘harsh, unrelenting’
- Middle Englishc. 1150–1500implācābleWiktionary, English implacable‘immitigable, unappeasable’
- Englishearliest quotation c. 1601–1602implacableWiktionary, English implacable. Earliest quotation in Wiktionary’s entry: c. 1601–1602, William Shakespeare, Twelfe Night, or What You Will: “He is knight dubb'd with vnhatche'd Rapier, and on…”
The story
From Middle English implācāble (‘immitigable, unappeasable’) from Old French implacable (‘harsh, unrelenting; implacable’) (modern French implacable), from Latin implācābilis (‘unappeasable, implacable; irreconcilable’), from im- (variant of in- (prefix meaning ‘not’)) + plācābilis (‘placable; appeasing, moderating, pacifying, propitiating; acceptable’) (from plācō (‘to assuage, pacify, placate; to appease; to reconcile’) + -bilis (suffix forming adjectives indicating a capacity or worth of being acted upon)).
Linked words
through Proto-Indo-European *pleHk- ‘pleasingness or permission’
through Proto-Indo-European *pleh₂- ‘wide and flat’
field, floor, explain, plane, palm, explanation, plain, clan, archipelago, fluke, explanatory, parma, playa, flounder, planar, palatine, placenta, esplanade, polonium, pelagic, plantar, lech, flay, veld, floe, purdah, llano, planta, 49 more
through Latin plācō ‘to assuage, pacify, placate’
Today it means
adj Not able to be placated or appeased.
Sources
Sources: Wiktionary, “implacable”. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / Latin plācō / implacable