'Unstable' in the Bible

So then, was I indecisive or capricious when I was [originally] planning this? Or the things I plan, do I plan in a self-serving way like a worldly man, ready to say, “Yes, yes” and “No, no” [at the same time]?

being a double-minded man, unstable and restless in all his ways [in everything he thinks, feels, or decides].

They have eyes full of adultery, constantly looking for sin, enticing and luring away unstable souls. Having hearts trained in greed, [they are] children of a curse.

speaking about these things as he does in all of his letters. In which there are some things that are difficult to understand, which the untaught and unstable [who have fallen into error] twist and misinterpret, just as they do the rest of the Scriptures, to their own destruction.