Flattery

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Middle English: from Old French flaterie, from flater ‘stroke, flatter’, probably of Germanic origin and related to flat1.

wiktionary

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From Middle English flaterye, flaterie, from Old French flaterie, from the verb flater(“to flatter”). Synchronically analyzable as flatter +‎ -y(forming abstract nouns).

etymonline

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flattery (n.)

early 14c., "dishonest praise, coaxing speech," from Old French flaterie "flattery, cajolery" (Modern French flatterie), from flater "to flatter" (see flatter).