Etymology
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adversary (n.)
"unfriendly opponent, enemy" (originally especially of Satan as the enemy of mankind), mid-14c., aduersere, from Anglo-French adverser (13c.), Old French adversarie (12c., Modern French adversaire) "hostile opponent, enemy," or directly from Latin adversarius "an opponent, rival, enemy," noun use of adjective meaning "opposite, hostile, contrary," literally "turned toward one," from adversus "turned against, turned toward, fronting, facing," figuratively "hostile, adverse, unfavorable," past participle of advertere "to turn toward," from ad "to" (see ad-) + vertere "to turn, turn back, be turned; convert, transform, translate; be changed" (see versus). The Latin word is glossed in Old English by wiðerbroca.
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adversarial (adj.)
"involving adversaries," by 1892, from adversary (n.) + -al (1). The older adjective was simply adversary (late 14c.), but the tendency to confuse it with the noun of the same form probably led to the creation of fresh adjectives (earlier examples are adversative, 1530s; adversarious, 1826). Related: Adversarially.
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foe (n.)

Old English gefea, gefa "foe, enemy, adversary in a blood feud" (the prefix denotes "mutuality"), from adjective fah "at feud, hostile," also "guilty, criminal," from Proto-Germanic *faihaz (source also of Old High German fehan "to hate," Gothic faih "deception"), perhaps from the same PIE source that yielded Sanskrit pisunah "malicious," picacah "demon;" Lithuanian piktas "wicked, angry," peikti "to blame." Weaker sense of "adversary" is first recorded c. 1600.

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snooker (v.)

"to cheat," early 1900s, from snooker (n.). Related: Snookered; snookering.

One of the great amusements of this game is, by accuracy in strength, to place the white ball so close behind a pool ball that the next player cannot hit a pyramid ball, he being "snookered" from all of them. If he fail to strike a pyramid ball, this failure counts one to the adversary. If, however, in attempting to strike a pyramid ball off a cushion, he strike a pool ball, his adversary is credited with as many points as the pool ball that is struck would count if pocketed by rule. [Maj.-Gen. A.W. Drayson, "The Art of Practical Billiards for Amateurs," 1889]
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Heinie (n.)
also Heine, Hiney, 1904 as a typical name of a German man, North American slang, from pet form of common German masc. proper name Heinrich (see Henry). Brought to Europe in World War I by Canadian soldiers (British soldiers called the adversary Fritz).
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fit (adj.)
"suited to the circumstances, proper," mid-15c., of unknown origin, perhaps from Middle English noun fit "an adversary of equal power" (mid-13c.), which is perhaps connected to fit (n.1). In athletics, "in condition, properly trained for action," from 1869. Related: Fitter; fittest. Survival of the fittest (1867) coined by H. Spencer.
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retiary (adj.)

1640s, of spiders, "spinning a web," from Latin retiarius, from rete "a net" (see rete). From 1650s as "net-like."

In Roman history, a retiarius was a gladiator who wore only a short tunic and carried a trident and a net. "With these implements he endeavored to entangle and despatch his adversary, who was armed with helmet, shield, and sword." [Century Dictionary].

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reconciliation (n.)

mid-14c., reconciliacioun, "renewal of friendship after disagreement or enmity, action of reaching accord with an adversary or one estranged" (originally especially of God and sinners), from Old French reconciliacion (14c.) and directly from Latin reconciliationem (nominative reconciliatio) "a re-establishing, a reconciling," noun of action from past-participle stem of reconciliare (see reconcile).

From 1729 as "act of harmonizing or making consistent." Other early noun forms included reconcilement (mid-15c.), reconciling (late 14c.).

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force (v.)
c. 1300, forcen, also forsen, "exert force upon (an adversary)," from Old French forcer "conquer by violence," from force "strength, power, compulsion" (see force (n.)). From early 14c. as "to violate (a woman), to rape." From c. 1400 as "compel by force, constrain (someone to do something)." Meaning "bring about by unusual effort" is from 1550s. Card-playing sense is from 1746 (whist). Related: Forced; forcing.
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Satan (n.)

proper name of the supreme evil spirit in Christianity, Old English Satan, from Late Latin Satan (in Vulgate in Old Testament only), from Greek Satanas, from Hebrew satan "adversary, one who plots against another," from satan "to show enmity to, oppose, plot against," from root s-t-n "one who opposes, obstructs, or acts as an adversary."

In Septuagint (Greek) usually translated as diabolos "slanderer," literally "one who throws (something) across" the path of another (see devil (n.)), though epiboulos "plotter" is used once.

In biblical sources the Hebrew term the satan describes an adversarial role. It is not the name of a particular character. Although Hebrew storytellers as early as the sixth century B.C.E. occasionally introduced a supernatural character whom they called the satan, what they meant was any one of the angels sent by God for the specific purpose of blocking or obstructing human activity. [Elaine Pagels, "The Origin of Satan," 1995]
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