fornication fornication /ˌfɔrnɪˈkeɪʃən/

noun

1. [Vulgar] Extramarital sex that willfully and maliciously interferes with marriage relations  ( adultery , criminal conversation , fornication [Vulgar] )
   extramarital sex that willfully and maliciously interferes with marriage relations
    Adultery is often cited as grounds for divorce
   adultery is often cited as grounds for divorce
   
2. [Vulgar] Voluntary sexual intercourse between persons not married to each other  ( fornication [Vulgar] )
   voluntary sexual intercourse between persons not married to each other