Where does “cupīdō” come from?

cupīdō (Latin) comes from Latin cupidus, from Latin -idus, from Proto-Italic *-iðos.

Ancestry of “cupīdō”, step by step

Step	Language	Word	Meaning
1	Latin	cupidus	eager, passionate; greedy; wanton, lecherous
2	Latin	-idus	tending to
3	Proto-Italic	*-iðos	—

cupīdō — Etymology, Origin & Word History | Etymology Explorer