ˈinˌsest noun
( -s )
Etymology: Middle English, from Latin incestus unchastity, incest (from incestus impure, unchaste, from in- in- (I) + -cestus, from castus pure, chaste) & incestum, from neuter of incestus — more at caste
1. : sexual intercourse or interbreeding between closely related individuals especially when they are related or regarded as related (as by reason of affinity or membership in a tribal kinship, group, or clan) within degrees wherein marriage is prohibited by law or custom — compare endogamy , exogamy , inbreeding
2. : the statutory crime of cohabitation, marriage, or sexual intercourse without marriage of parties related to each other within the degrees of consanguinity or often of affinity within which marriage is prohibited by law