c. 1300, "of or concerning the spirit" (especially in religious aspects), from Old French spirituel, esperituel (12c.) or directly from a Medieval Latin ecclesiastical use of Latin spiritualis "of or pertaining to breath, breathing, wind, or air; pertaining to spirit," from spiritus "of breathing, of the spirit" (see spirit (n.)). Meaning "of or concerning the church" is attested from mid-14c. Related: Spiritually. An Old English word for "spiritual" was godcundlic.
In avibus intellige studia spiritualia, in animalibus exercitia corporalia [Richard of St. Victoror (1110-1173): "Watch birds to understand how spiritual things move, animals to understand physical motion." - E.P.]
1852, "one who believes in the ability of the living to communicate with the dead via a medium," from spiritual + -ist (also see spirit (n.)). Earlier (1640s) "one with regard for spiritual things." Related Spiritualistic.
Every two or three years the Americans have a paroxysm of humbug — ... at the present time it is Spiritual-ism. [J.Dix, "Transatlantic Tracings," 1853]
late 14c., spiritualite, "the clergy," also "ecclesiastical property; things pertaining to the Church," from Anglo-French spiritualite, Old French espiritualite, and directly from Late Latin spiritualitatem (nominative spiritualitas), from Latin spiritualis (see spiritual). Meaning "quality of being spiritual" is from c. 1500; seldom-used sense of "fact or condition of being a spirit" is from 1680s. Also in early use spiritualty (late 14c.).
English is blessed with multiple variant forms of many words. But it has made scant use of them; for every pair historic/historical; realty/reality, or luxuriant/luxurious there is a spiritualty/spirituality or a specialty/speciality, with two distinct forms, two senses requiring differentiation, hundreds of years gone by, and but little progress made in in sorting them out.
"knowledge," especially "special knowledge of spiritual mysteries," 1703, from Greek gnōsis "a knowing, knowledge; a judicial inquiry, investigation; a being known," in Christian writers, "higher knowledge of spiritual things," from PIE *gnō-ti-, from root *gno- "to know."