Not – нет
From Middle English not, nat, variant of noght, naht (“not, nothing”), from Old English *nōht, nāht (“nought, nothing”), short for nōwiht, nāwiht (“nothing”, literally “no thing, no creature”), corresponding to nā (“no”) + wiht (“thing, creature”). Cognate with Scots nat, naucht (“not”), Saterland Frisian nit (“not”), West Frisian net (“not”), Dutch niet (“not”), German nicht (“not”). Compare nought and aught. More at no, wight.
Negative particle, mid-13c., unstressed variant of noht, naht "in no way" (see naught). As an interjection to negate what was said before or reveal it as sarcasm, it is first attested 1900; popularized 1989 by "Wayne's World" sketches on "Saturday Night Live" TV show. To not know X from Y (one's ass from one's elbow, shit from Shinola, etc.) was a construction first attested c. 1930. Double negative construction not un- was derided by Orwell, but is persistent and ancient in English, popular with Milton and the Anglo-Saxon poets.
Not и нет в украинском языке - ні.Нет в смысле "отсутствует" в украинском - немає.