Hardly

wiktionary

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From Middle English hardely, hardliche, from Old English heardlīċe(“boldly; hardily; without ease; in a way that causes pain; not easily; only by degrees”), equivalent to hard +‎ -ly. Compare Dutch hardelijk, German härtlich.

etymonline

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hardly (adv.)

c. 1200, "in a hard manner, with great exertion or effort," from Old English heardlice "sternly, severely, harshly; bravely; excessively" (see hard (adj.) + -ly (2)). Hence "assuredly, certainly" (early 14c.). Main modern sense of "barely, just" (1540s) reverses this, via the intermediate meaning "not easily, with trouble" (early 15c.). Formerly with superficial negative (not hardly). Similar formation in Old Saxon hardliko, German härtlich, Old Danish haardelig.