incest

IPA/ˈɪnsest/
KK[ˈɪnsˌɛst]IPA/ˈɪnsest/

incest — noun

1. a sexual relationship between close blood relatives, such as two siblings or a p

1.nounC1
Definition

a sexual relationship between close blood relatives, such as two siblings or a parent and their child, that is prohibited by law or strongly condemned by most societies

Example

In many countries, the law states that incest is a criminal offense punishable by imprisonment.

legal register: incest + criminal offense

Ancient Egyptian royalty sometimes practiced incest to keep power within the ruling family.

collocation: practiced incest

Common collocations
  • commit incest
  • practice incest
  • be accused of incest
  • incest between siblings
  • incest within the royal family
  • brother-sister incest
  • parent-child incest
  • a case of incest
  • incest survivor
Synonyms
  • inbreeding

    More common in biology and animal breeding; less tied to legal prohibition, more to genetic reproduction between close relatives

  • family sexual abuse

    Emphasizes the harm and power imbalance; narrower than incest, which is a legal term covering any prohibited sexual relationship between relatives

Grammar Patterns

incest + between [people]

incest + within [family/society]

Usage Note

Frequently appears in legal, clinical, and social-work contexts. What counts as incest varies across legal systems — some jurisdictions restrict it to parent-child and sibling relationships, while others extend it to cousins, step-relatives, or in-laws. The adjective form is 'incestuous'.

Common Mistakes

The documentary explored incest relationships in ancient cultures.
The documentary explored incestuous relationships in ancient cultures.
'incest' is a noun; its adjective form is 'incestuous'.
They were accused of inbreeding with each other.
They were accused of incest.
'inbreeding' is used mainly for animal populations or genetics; 'incest' is the correct legal and social term for humans.

Word family

  • incestuous
    adjectiveC1
  • incestuously
    adverbC2

Synonym discussion

Sense: noun/1

Incest is the broad legal and social term for sexual relations between close blood relatives, such as siblings or a parent and child. Inbreeding focuses on the genetic consequences of reproduction between relatives and is most often used in animal breeding or population genetics, not in legal contexts. Consanguinity is a neutral, formal term for the state of being related by blood; it describes the relationship itself, not any sexual act, so it is not interchangeable with incest. Family sexual abuse overlaps with incest but adds a connotation of coercion or power abuse, typically within a parent-child dynamic. Use incest when referring to the legal prohibition or social taboo; use inbreeding when discussing heredity in animals or isolated human populations; use consanguinity in formal kinship or demographic writing.

incest ↗inbreeding ↗consanguinity ↗family sexual abuse

Common collocations

Nouns

  • incest survivor
  • incest case
  • incest victim
  • incest taboo
  • incest laws

Phrases

  • to be accused of incest
  • to be convicted of incest
  • a history of incest

Prepositions

  • incest between
  • incest within
  • incest among

Etymology

LatinFrenchEnglish

Incest comes from Latin 'incestus', meaning 'impure' or 'unchaste', formed by the prefix 'in-' (not) and 'castus' (pure, chaste). It entered English through Old French in the 13th century, originally referring to any unchaste act, before narrowing to the specific meaning of sexual relations between close relatives over the following centuries.