I think we have to accept there are different meanings of the word 'spiritual' although atheists will probably claim superiority for theirs given their generic linguistic totalitarianism.
Oh give it a rest Vlad - yet more record stuck in a groove non-sense.
Sure there are many definitions of 'spiritual' and many reasons why people might describe themselves as 'spiritual' - actually I gave a list of some examples really early on in this thread. But actually atheists are fairly unlikely to use the term about themselves, certainly far less likely than religious people. So it isn't really atheists hi-jacking definitions for their own purposes. Rather it is the religious who are much more likely to do so, largely to try to claim that that people who describe themselves as 'spiritual' are actually a hidden group of religious people and therefore that the decline in religiosity is rather less than we thought. Indeed the article Sriram linked to in the OP makes exactly this claim. The claim is, of course, non-sense as the evidence demonstrates. However the point remains that it is the religious not atheists who tend to twist definitions of 'spiritual' to their own ends.