Where does “printru” come from?

printru (Romanian) comes from Latin per, from Latin Ad, from Latin illic, from Latin ille, from Latin olle, from Proto-Italic *olnos — that.

Ancestry of “printru”, step by step

Step	Language	Word	Meaning
1	Latin	per	through, by means of; throughout, during
2	Latin	Ad	toward, to
3	Latin	illic	he, she, it, yonder, that, overthere; in that...
4	Latin	ille	that; those; "; demonstrative pronoun "; that...
5	Latin	olle	Archaic form of ille
6	Proto-Italic	*olnos	that