incest

American

[in-sest] / ˈɪn sɛst /

noun

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

incest British

/ ˈɪnsɛst /

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

incest Cultural

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

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

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

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

State Rep. Delisha Boyd, a Democrat who put forward a rape and incest exception bill in Louisiana, shared that she was conceived when her mother was raped at 15 by an older man.

From Salon • Dec. 5, 2023

However, the 2010 constitution, combined with a wider body of law, does allow abortion when "the life or health of the mother is in danger" or when the pregnancy has resulted from rape or incest.

From BBC • Nov. 26, 2023

“It wasn’t too different for Western audiences. Also, this theme of revenge and incest is familiar in both the East and the West from older classics, for instance the Bible or Greek mythology.”

From Los Angeles Times • Aug. 16, 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

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023