adultery

Etymology

From the Old French scholarly form adultere (“violation of conjugal faith”) (in Bernard of Clairvaux, Sermons, 12c.), from Latin adulterium, from adulter. Replaced the older form avoutrie, from the popular Old French forms avouterie or aoulterie. Compare French adultère (“adultery”). Displaced Old English ǣwbryċe. Not related to adult.

noun

1. Sexual intercourse by a married person with someone other than their spouse. See more synonyms at Thesaurus:cuckoldry
   She engaged in adultery because her spouse has a low libido, while hers is very high.
   So also that copulation which in one City is Matrimony, in another will be judged Adultery. 1651, Thomas Hobbes, De Cive
   Under modern statutory law, some courts hold that the unmarried participant isn't guilty of adultery (that only the married participant is) 2009, Garner's Modern American Usage, page 22
2. (biblical) Lewdness or unchastity of thought as well as act, as forbidden by the seventh commandment.
3. (biblical) Faithlessness in religion.
4. (obsolete) The fine and penalty formerly imposed for the offence of adultery.
5. (ecclesiastical) The intrusion of a person into a bishopric during the life of the bishop.
6. (political economy) Adulteration; corruption.
7. (obsolete) Injury; degradation; ruin.
   […] you might wrest the Caduceus out of my hand, to the adultery and spoil of Nature […] 1616, Ben Jonson, “Mercury Vindicated from the Alchemists”, in Thomas Hodgkin, editor, The Works of Ben Jonson, published 1692, page 378