"exuberant in growth or quantity," 1530s, from French luxuriant and directly from Latin luxuriantem (nominative luxurians), present participle of luxuriare "have to excess, grow profusely" (see luxuriate). Related: Luxuriantly.
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.
Old English ranc "proud, overbearing, haughty, showy," senses now obsolete, from Proto-Germanic *rankaz (source also of Danish rank "right, upright," German rank "slender," Old Norse rakkr "straight, erect"), which is of uncertain origin, possibly related to Old Norse and Old English rinc "man, warrior." Related: Rankly; rankness.
In reference to plant growth, "vigorous, luxuriant, abundant, copious" (also figurative) it is recorded from c. 1300. The sense also evolved in Middle English to "large and coarse" (c. 1300), then to "corrupt, loathsome, foul" (mid-14c.), perhaps via the notion of "excessive and unpleasant," perhaps also influenced in this by French rance "rancid." Specifically as "having an offensive, strong smell" by 1520s. In Middle English also "brave, stout-hearted; splendid, admirable." In 17c. it also could mean "lewd, lustful."
The development of the word in Eng. is, however, far from clear, as the OE. uses are not quite the primitive ones. In ME. also it chiefly occurs in alliterative verse, app. more for convenience than to express definite meanings. In the later language the chief difficulty is to decide which of the more original senses are represented in the transferred uses. [OED]
Much used 16c. as a pejorative intensive (as in rank folly). This is possibly the source of the verb meanings "to reveal another's guilt" (1929, underworld slang) and that of "to harass, insult, abuse," 1934, African-American vernacular, though this also may be so called from the role of the activity in establishing social hierarchy (and thus from rank (n.)).