From Wiktionary, the free dictionary
làng (“village”) + nước (“country”).
làng nước
- (now literary) one's village
Bớ làng nước ơi, có ăn trộm!- Everyone! There's a thief!
- (by extension, humorous, intimate) people within the same scene or subculture
Làng nước ơi, tui mới kiếm ra cái web tải phim này nè.- Lads, I just found this website for movie torrents!