Where does “グルジア” come from?

グルジア (Japanese) comes from Russian Гру́зия, from Russian грузи́н, from Old East Slavic гурзи — Georgians.

Ancestry of “グルジア”, step by step

Step	Language	Word	Meaning
1	Russian	Гру́зия	—
2	Russian	грузи́н	—
3	Old East Slavic	гурзи	Georgians

グルジア — Etymology, Origin & Word History | Etymology Explorer