Covert

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Middle English (in the general senses ‘covered’ and ‘a cover’): from Old French, ‘covered’, past participle of covrir (see cover).

wiktionary

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From Middle English covert, from Old French covert, past participle of covrir(“to cover”) (corresponding to Latin coopertus); cognate to cover.

etymonline

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covert (adj.)

"hidden, private, secret, concealed," c. 1300, from Old French covert (Modern French couvert) "hidden, obscure, underhanded," literally "covered," past participle of covrir "to cover" (see cover (v.)). Related: Covertly.