"spiritual" - derived from the latin term "spiritus" - and therefore originated before monotheism.
originally, it was used to refer to the "soul" or "subconsciousness" ie the psyche, seperate from our physical selves.
lt literally comes from "spirare" meaning "breathe" plus the verb action "..itus" - ie "breathing"/"to breathe" or "the action of breath".
breathing represents something different from concious mind and physical body, we dont actively control our breathing, and especially before scientific explanation its easy to view the part in control of this function as a kind of inner "spirit".
now the term is ambiguous to say the least.
personally, as a rationalist, logical thinker, athiest, skeptic and myth buster I avoid the term entirely.
for me it carries too much meaningless ambiguity, and is most often (i didnt say always!) used by the kind of "new age" hippy, for want of a better term.
what i mean is it most commonly is used by the uneducated or "faith" adopting individual, ie the non-empirical, non enquiring rationalist who believes in the paranormal, or believes without evidence or the need for it. usually it accompanies psychedelic cliche, a mish mash of misunderstood and conflicting ideologies, spiritual healing, crystals, homeopathy, psychics, auras, and other such delusions and for this reason I cant stand the term.
MOST irritatingly and most commonly the self proclaimed "spiritual" (yuck) folks i refer to are the kind who spout such nonsense as "evolution is only a theory" - fuck! yes a scientificly proven "theory" ie a "fact".
much like the "theory" of relativity.
or the "theory" of gravity!
hopefully these people feel the same way about the theory of gravity and might just float the fuck away!
of course this is based upon my experience and IMHO only.
altruism is not spiritual, neither is being sensitive, compassionate, emotionally in tune, self aware, or holding an innate wonder of the natural world and the beauty of the nature of things.
I believe I am all of the above.
However, usually i find the term "spiritual" to be used by the inarticulate or those devoid of an eloquent command of English, slapped in place of a more descriptive, accurate and specific adjective.
of course, before i get flamed, this is a subjective viewpoint, a personal dislike for the word and its connotations based upon the majority of those I have encountered.
actually I made a track VERY relevant to this subject, which somes up the kind of "spiritual" individuals im referring to.
Well worth a listen if you are a rationalist, or skeptic, or generally someone who has the common sense to view the emprical evidence and educate themselves before adopting a half-baked faith-based belief system.
http://soundcloud.com/bigman-productions/the-storm
or remix By wicked fretmaster, felow bluelighter and top geezer "Nomy" made in the non-electronic music forum - thread entitled "making music with fellow bluelighters"
http://soundcloud.com/liquidmuse/storm-latest-full-mix