Supine

Supine (pronounced soo-pahyn)

(1) Lying on the back, face or front upward.

(2) Inactive, passive, or inert, especially from indolence or indifference; displaying no interest or animation; lethargic, apathetic or passive towards something.

(3) Being reluctant to take action due to indifference or moral weakness

(4) Inclining or leaning backward; inclined, sloping (now probably obsolete except for poetic or historic use).

(5) Of the hand, forearm or foot, turned facing toward the body or upward: with the thumb outward (palm up), or with the big toe raised relative to the little toe.

(6) A technical rule in Latin; a noun form derived from verbs, appearing only in the accusative and the dative-ablative.  Often used to express purpose with verbs of motion

(7) A technical rule in English; the simple infinitive of a verb preceded by to.

(8) A descriptor (in English) for an analogous form in some other language.

(9) Inclining or leaning backward; inclined, sloping (now rare and used only as a literary or poetic device).

1490-1500: From the Latin supīnus (bent backwards, thrown backwards, lying on the back (and figuratively "inactive, indolent"), ultimately from the primitive Indo-European sup & up.  It was cognate with the Catalan supí, the Italian supino (on one's back), the Old French sovin, the Middle French souvin, supin & supin, the Anglo-Norman supin (which persists in modern French as supin), the Old Occitan sobin & sopin, the Portuguese supino and the Spanish supino.  The verb supinate dates from 1831 in the sense of "to place the hand so that the palm is turned upward" and was from the Latin supinatus, past participle of supinare (to bend back) and related to supinus (the related forms being supinated, supinating & supinators.  The adjective was from the Latin supīnus, the construct being sup- (in the sense of “under”) + -īnus (of or pertaining to).  The noun came later, from the Late Middle English supin (as in “supine of a Latin verb”) or the Middle French supin ((grammar) supine) all from the Latin supīnum (short for supīnum verbum (supine verb)) from supīnus.  It partially displaced the Old English upweard (upward, supine), from which Modern English gained "upward".  The now rarely used sense of "morally or mentally inert, negligent, listless, heedless" was in use in English by the early seventeenth century and the noun supinity is used in this context.  Supine is a noun & adjective, supination, supinator, supinity & supineness are nouns, supinate is a verb, supinated is a verb & adjective and supinely is an adverb; the noun plural is supines.

Lindsay Lohan supine from a photo-shoot by Terry Richardson (b 1965) for Love Magazine (2012).

The technical rule in Latin grammar: "the verbal noun formed from the past participle stem" is from the Late Latin supinum verbum (supine verb), the origin of which is undocumented but thought so called because, though furnished with a noun case ending, it "falls back" on the verb.  In Latin grammar, supine is best thought of as a practice rather than a rule and it’s observed rather than understood or applied.  The verbal noun is used in only a few syntactic constructions and occurs in only two cases, an accusative in -tum or -sum and an ablative in -tū or –sū although the accusative form is sometimes listed by scholars as the fourth principal part of the Latin verb, a fine distinction only they understand.

Although there was a war going on, the misuse of "supine" and "prone" (by fellow  physicians!) so disturbed Dr Edwin H Shepard MD of Syracuse, NY he wrote a letter to the editor of the Journal of the American Medical Association (JAMA) which was published in the edition of 27 May 1944.  Eighty years on, Very Well Health advises doctors the trick to remember the difference between supine and prone is: "supine contains the word "up", reminding you you are face up in this position while prone contains the word "on" which you can use to remember you are lying on your face or stomach."

So, strictly speaking, "supine" means lying face upwards while the words for lying face downwards are "prostrate" or "prone" but these have long been used loosely (probably increasingly so) for lying flat in any position.  Thus, the antonym correctly is "nonsupine" (or "non-supine") but "prone" is sometimes used, doubtlessly leaving many baffled, including, clearly, some physicians.  The synonym resupine is rare and may be functionally extinct.