Where does “curios” come from?

curios (Old French) comes from Latin curiosus, from Latin -osus, from Old Latin -osos, from Latin ont-to-s, from Latin -o-wont-to-s.

Ancestry of “curios”, step by step

Step	Language	Word	Meaning
1	Latin	curiosus	Careful, diligent, thoughtful, devoted;...
2	Latin	-osus	-ose, -ous; full of, overly, prone to
3	Old Latin	-osos	accusative masculine plural of -ōsus
4	Latin	ont-to-s	—
5	Latin	-o-wont-to-s	—