Old English synn "moral wrongdoing, injury, mischief, enmity, feud, guilt, crime, offense against God, misdeed," from Proto-Germanic *sundiō "sin" (source also of Old Saxon sundia, Old Frisian sende, Middle Dutch sonde, Dutch zonde, German Sünde "sin, transgression, trespass, offense," extended forms), probably ultimately "it is true," i.e. "the sin is real" (compare Gothic sonjis, Old Norse sannr "true"), from PIE *snt-ya-, a collective form from *es-ont- "becoming," present participle of root *es- "to be."
The semantic development is via notion of "to be truly the one (who is guilty)," as in Old Norse phrase verð sannr at "be found guilty of," and the use of the phrase "it is being" in Hittite confessional formula. The same process probably yielded the Latin word sons (genitive sontis) "guilty, criminal" from present participle of sum, esse "to be, that which is." Some etymologists believe the Germanic word was an early borrowing directly from the Latin genitive. Also see sooth.
Sin-eater is attested from 1680s. To live in sin "cohabit without marriage" is from 1838; used earlier in a more general sense. Ice hockey slang sin bin "penalty box" is attested from 1950.
c. 1200, remissioun, "forgiveness or pardon (of sins)," from Old French remission "forgiveness (of sins), relief" (12c.) and directly from Latin remissionem (nominative remissio) "relaxation, diminishing," etymologically "a sending back, sending away," noun of action from past-participle stem of remittere "slacken, let go, abate" (see remit).
From late 14c. as "release from duty or obligation." Of diseases, fevers, "abatement, temporary subsidence," from early 15c. General sense of "diminution of force or effects" is from c. 1600. By 1736 as "abatement of penalty or punishment."
Sense of "leniency, forbearance of restraint or control of another, gratification of desire or humor" is attested from late 14c. That of "yielding to one's inclinations" (technically self-indulgence) in English is from 1630s. In British history, Indulgence also refers to grants of certain liberties to Nonconformists under Charles II and James II, as special favors rather than legal rights. The sale of indulgences in the original Church sense was done at times merely to raise money and was widely considered corrupt; the one in 1517 helped to spark the Protestant revolt in Germany.
late 14c., relaxacioun, "a rupture, a hernia" (a sense now obsolete); mid-15c., "remission of a burden or penalty," from Old French relaxacion (14c.) and directly from Latin relaxationem (nominative relaxatio) "an easing, mitigation, relaxation," noun of action from past-participle stem of relaxare "loosen, open, stretch out" (see relax).
Meaning "relief from hard work or ordinary cares; a state or occupation intended to give mental or bodily relief after effort or ordinary occupations and cares" is from 1540s. Sense of "remission or abatement of rigor or intensity" is from 1690s.
before vowels Sin-, word-forming element meaning "Chinese," 1879, from Late Latin Sinæ (plural) "the Chinese," from Ptolemaic Greek Sinai, from Arabic Sin "China," probably from Chinese Ch'in, name of the fourth dynasty of China (see China).
statement acknowledging or confessing sin; Latin, literally "I have sinned;" first person singular preterite indicative active of peccare "to sin" (see peccadillo). Related: peccavimus "we have sinned;" peccavit "he has sinned."