Where does “ineptitūdō” come from?

ineptitūdō (Latin) comes from Latin ineptus, from Proto-Italic enaptos.

Ancestry of “ineptitūdō”, step by step

Step	Language	Word	Meaning
1	Latin	ineptus	unsuitable; impertinent, improper, tasteless;...
2	Proto-Italic	enaptos	—