Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
spiritual, spiritous, spirituous (adjs.)
All three adjectives come from the Latin spiritus, meaning “a breath.” Spiritual has to do with the soul or other intangible “breaths,” as in affairs of the spirit, whereas spirituous and spiritous are highly specialized and refer to distilled alcoholic spirits only. He preferred spiritual pleasures to spirituous [or spiritous] ones. Spiritous once also meant “pure,” but that sense is now archaic, perhaps obsolescent.
