Even more impossible than impossible. Quite possibly the most impossiblest thing in the world.

Unpossible, that which can’t be done just yet.

We have the word impossible, but we need to differentiate between two sorts of things. The Impossible is that which, by definition, can never be done. We need another word, Unpossible, that which can’t be done just yet.

The state of not being possible simply and solely because prevalent thinking refuses to allow it.

Something that should be possible, however is consistently failed at so hard that it inverts itself and becomes the opposite of possible, thus unpossible.

Not quite impossible, but pretty close.

Something that at first seems impossible. If you change your thinking about it it becomes possible.

Incorrect way of saying impossible, rarely used.