Where does “Ciuperceni” come from?

Ciuperceni (Romanian) comes from Hungarian -eni, from Hungarian -é-, from Hungarian -d, from Middle Welsh -nt — 3rd person plural verb ending.

Ancestry of “Ciuperceni”, step by step

Step	Language	Word	Meaning
1	Hungarian	-eni	Used to form the infinitive; "For the other...
2	Hungarian	-é-	—
3	Hungarian	-d	your; Used in the second-person singular definite...
4	Middle Welsh	-nt	3rd person plural verb ending