Where does “ignorant” come from?

ignorant (Old French) comes from Latin ignōrāns, from Latin ignōrō, from Proto-Indo-European ǵneh₃- — to know.

Ancestry of “ignorant”, step by step

Step	Language	Word	Meaning
1	Latin	ignōrāns	—
2	Latin	ignōrō	—
3	Proto-Indo-European	ǵneh₃-	to know

ignorant — Etymology, Origin & Word History | Etymology Explorer