If two or more people are inseparable, they are such good friends that they spend most of their time together.

When we were kids Zoe and I were inseparable. 我和佐伊在孩提时代形影不离。

If two or more things are inseparable, they are so closely connected that they cannot be considered separately.

Unemployment and inner city decay are inseparable issues which must be tackled together. 失业与市中心贫民区的破败是分不开的问题，必须一起解决。