Where does “nitheren” come from?

nitheren (Middle English) comes from Old English niþerian, from Old English niþer, from Proto-Germanic niþer, from Proto-Indo-European niter.

Ancestry of “nitheren”, step by step

Step	Language	Word	Meaning
1	Old English	niþerian	to depress, abase, bring low, humiliate, oppress,...
2	Old English	niþer	down; downstairs
3	Proto-Germanic	niþer	down, downwards
4	Proto-Indo-European	niter	—

nitheren — Etymology, Origin & Word History | Etymology Explorer