A supportable argument, statement, etc. can be shown to be true using evidence.

If something bad is supportable, you are able to accept it or continue despite it.

He looked for something to make his wait more supportable. 他在找东西让等待变得容易忍受一些。

used to describe an activity that can continue without problems

Their economy has shrunk by a barely supportable 15–20 percent. 他们的经济缩水了15-20%，几乎难以为继。