Where does “nongradual” come from?

nongradual (English) comes from English non, from French non, from Old French non, from Latin nōn, from Old Latin noenum, from Proto-Indo-European óynos — one; single.

nongradual (English): Not gradual; occurring suddenly

Definitions

Not gradual; occurring suddenly

Ancestry of “nongradual”, step by step

nongradual traces back through two separate lines of ancestry.

via English non

Step	Language	Word	Meaning
1	English	non	Obsolete form of none
2	French	non	no; not; a no, a negative response
3	Old French	non	no; not; Alternative form of nom
4	Latin	nōn	not
5	Old Latin	noenum	—
6	Proto-Indo-European	óynos	one; single

via English gradual

Step	Language	Word	Meaning
1	English	gradual	Proceeding or advancing by small, slow, regular...
2	Medieval Latin	gradualis	—
3	Latin	gradus	a step, pace; a stage, degree; a rank
4	Proto-Italic	graðus	—
5	Proto-Indo-European	gʰradʰ-	—

Every word from Proto-Indo-European óynos →Every word from Old Latin noenum →Every word from Latin nōn →