incest

باللغة العربية: زِنَا مَحَارِم، سِفَاح الْقُرْبَى

1. Sexual relations between close relatives, especially immediate family members and sometimes first cousins, usually considered taboo. (uncountable) · Genetic problems caused by incest are thought to have plagued many royal families in the Middle Ages.
2. Romantic relationships between close relatives, also widely taboo. (uncountable)

الجمع incests