adultery

noun

1. (countable, uncountable)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.”

   “Under modern statutory law, some courts hold that the unmarried participant isn't guilty of adultery (that only the married participant is)”

   “Ironically, the detergent industry-sponsored "soap operas" that are central to modern afternoon television programming promise (mostly) female viewers both relief from drudgery and escape into the dramatic, crisis-filled on-air world of (laundryless) marriages, adulteries, and other relationships.”

2. (broadly, countable, uncountable)Lewdness or unchastity of thought as well as act, as forbidden by the sixth/seventh commandment; sinful sexual behavior as a category.

   “Thou shalt not commit adultery.”

3. (countable, uncountable)Faithlessness in religion.

   “And it came to pass through the lightness of her whoredom, that she defiled the land, and committed adultery with stones and with stocks.”

4. (countable, obsolete, uncountable)The fine and penalty formerly imposed for the offence of adultery.
5. (countable, uncountable)The intrusion of a person into a bishopric during the life of the bishop.
6. (countable, uncountable)Adulteration; corruption.
7. (countable, obsolete, uncountable)Injury; degradation; ruin.

   “[…] you might wrest the Caduceus out of my hand, to the adultery and spoil of Nature […]”