1. 闭塞的地方；与世隔绝的地方
A backwater is a place that is isolated.

2. 停滞（或落后）的地方；一潭死水
If you refer to a place or institution as a backwater, you think it is not developing properly because it is isolated from ideas and events in other places and institutions.

1. a place or condition in which no development or progress is occurring

e.g. the country is an economic backwater

2. a body of water that was created by a flood or tide or by being held or forced back by a dam

e.g. the bayous and backwaters are breeding grounds for mosquitos