Where does “opposen” come from?

opposen (Middle English) comes from Old French opposer, from Latin ob, from Proto-Italic *op.

Ancestry of “opposen”, step by step

Step	Language	Word	Meaning
1	Old French	opposer	—
2	Latin	ob	in the direction of, to, towards; on account of,...
3	Proto-Italic	*op	—

opposen — Etymology, Origin & Word History | Etymology Explorer