Preacher

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Middle English: from Old French precheor, from ecclesiastical Latin praedicator, from the verb praedicare (see preach).

wiktionary

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From Middle English precher, prechere; partly equivalent to preach +‎ -er, and partly continuing Middle English prechour, prechiour, from Old French preecheor (French prêcheur), from Latin praedicator(“public praiser, proclaimer”). See preach.

Displaced native Old English bydel.

etymonline

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preacher (n.)

"one authorized or appointed to discourse publicly on religious subjects," c. 1200, prechour, from Old French preecheor "preacher" (Modern French prêcheur), from Latin praedicatorem (nominative praedicator) "public praiser, eulogist," literally "proclaimer" (see preach). Slang short form preach (n.) is recorded by 1968, American English.