Is it possible to be a 'spiritual atheist'?

The problem is that definitions of "spirituality", like definitions of "God", are notoriously plastic and imprecise. I would say that there seems to be some commonality of experience in the "sense of awe". That's not so well-defined either, but probably will mean something to the reader. Other than that, I feel it good manners to let others label themselves as they please. It's not for me to usurp that. Whether you call yourself atheist, agnostic, or believer in some tradition, it doesn't really say all that much of significance about the person, who, really, has to contain a lot more than the shorthand implies.

Of course you can be spiritual without believing in God. That's what Gnosticism is all about

Of course. Spirituality and religion exist independently of one another

If an atheist is spiritual, he is probably either agnostic or pagan, not atheist. Atheists do not believe in anything.

Yes I think you can believe in spirit without necessarily invoking gods.

For example Buddhists can be like that.

yes

Drink rum, vodka, whiskey, brandy,. their full of spirits