“Not” feels like one of the simplest words in English. But it's actually derived from a three-part compound.

It started as nāwiht, Old English for ‘nothing’: the negator ne plus ā (‘always, ever’) plus wiht (‘thing, being’). Ne-ā-wiht. Not ever a thing.

Centuries of daily use ground it down: nāwiht became naught or nought, then just not.

We say it dozens of times a day with no sense that we're using the battered remnant of a whole phrase that meant ‘nothing at all.’