Where does “ghrãmustean” come from?

ghrãmustean (Aromanian) comes from Aromanian -ean, from Proto-Slavic -ěninъ.

Ancestry of “ghrãmustean”, step by step

Step	Language	Word	Meaning
1	Aromanian	-ean	Forms adjectives and nouns indicating origin or place of birth (such as from a certain city or region)
2	Proto-Slavic	-ěninъ	—