The short, simple English word not is a contraction of an Old English phrase "not ever a thing".
wiht: "creature, person, thing"
(Or really, a West Germanic contraction, it also gives German nicht and Dutch niet).
Equivalent to Germanic *ne-aiwa-wihtã or Proto-Indo-European *ne-h₂óyu-wektom.
Similarly, never is ne ā in fēore: "not ever in life" (or, "not on your life!"). The equivalent German, nimmer, is from OHG ne io mēr: "not ever more" (or, "nevermore").
Compare how the French negation was once ne, but was augmented with, for instance, pas: "step", from approximate Vulgar Latin nec alare passum: "to not go a single step".
These are examples of a broader pattern of function words getting worn down by use, and then when they get too small, augmenting them back up again.