one who is extremely familiar with the surroundings; a local
Definitions (粵典–words.hk)
名詞
對一個地方瞭如指掌嘅人(量詞:個) person who knows a place very well
佢係呢區嘅地膽,住咗喺度五十年喇。
佢系呢区嘅地胆,住咗喺度五十年喇。
keoi5 hai6 ni1 keoi1 ge3 dei6 daam2, zyu6 zo2 hai2 dou6 ng5 sap6 nin4 laa3. He has been living here for 50 years. He knows this place well.