I think it's an important question for some people to ask, but I feel it's so easy to get lost in words and concepts that put us back to sleep when trying to define a word like this. Perhaps if I was truly awake the answer would come to me without any thought, or perhaps if I were truly awake I'd forget English and just reply with some gibberish that inspired something in you.

The only thing I can come up with is that to be awake is to be blind to both future and past and focused entirely in the now. So many of us think that we can do this, and to some extent we can, but I believe we are just dipping our feet in. To be immersed in the now, the world of form will begin to blend with the formless. I suppose we can visit there, but it's rare to find someone who can be there at will.

I might have a totally different answer tomorrow.