Clearly

wiktionary

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From Middle English clerli, clerely, clerelych, cleerliche, clerliche, equivalent to clear +‎ -ly.

etymonline

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clearly (adv.)

c. 1300, of vision and speech, "in a clear manner, without obscurity," from clear (adj.) + -ly (2). Meaning "evidently" is from 1560s; as a parenthetical expression in argument, "it is clear," recorded from 1867.