incest

American  

[in-sest] / ˈɪn sɛst /

noun

1. sexual intercourse between closely related persons.

2. the crime of sexual intercourse, cohabitation, or marriage between persons within the degrees of consanguinity or affinity wherein marriage is legally forbidden.

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incest British  

/ ˈɪnsɛst /

noun

1. sexual intercourse between two persons commonly regarded as too closely related to marry

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incest Cultural  

1. Sexual relations between relatives who are forbidden by law to marry; for example, between father and daughter or mother and son.

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Discover More

Though each society has its own system for determining the range of people who fall into this category, every society has an incest taboo of some sort.

Etymology

Origin of incest

1175–1225; Middle English < Latin incestus (noun) sexual impurity, derivative of incestus (adj.) profane, sexually impure ( in- in- ³ + -cestus combining form of castus chaste ), by analogy with v. nouns derived with -tus

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Explanation

Incest is a word for any kind of sex between family members: parent and child, brother and sister, or cousin and cousin. There are many disturbing things in the world, and incest is near the top of the list. Incest is when people who are related have sex. This could take many forms: a parent raping a child is incest. Two first cousins marrying is also incest. Different states have different rules for how distantly related two people need to be to avoid incest, mostly because children born from incest often have serious health problems.

Example Sentences

See Examples For:

incest

Recognizing that women would now have to live under the restriction, DuBuisson wanted to make sure victims of rape and incest could terminate their pregnancies.

From Salon ● Jun. 8, 2026

After the movie came out, Lindo says, he met an incest survivor who said she appreciated the humanity he gave to a seemingly monstrous character.

From The Wall Street Journal ● Mar. 3, 2026

In the 1960s, legislators introduced additional exceptions: for sexual assault, incest, fetal disability and certain health risks.

From Los Angeles Times ● Dec. 13, 2023

There’s a patchwork of policies for other exceptions, including for pregnancies caused by rape or incest.

From Seattle Times ● Dec. 12, 2023

"All this of snakes and incest is droll, but it changes nothing. You may well have the better claim, Stannis, but I still have the larger army."

From "A Clash of Kings" by George R.R. Martin

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