Disprove

wiktionary

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From Middle English disproven, dispreven, from Old French desprover, from des- + prover.

etymonline

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disprove (v.)

"prove to be false or erroneous," late 14c., from Old French desprover "refute, contradict," from des- (see dis-) + prover "show; convince; put to the test" (see prove). Related: Disproved; disproving; disprovable. Middle English also had dispreven, from Old French desprover, with substitution of prefix.