fornicate

for|ni|cate /f'ɔː^rnɪkeɪt/ (fornicates fornicating fornicated)
[V-RECIP] pl-n V, V with n, V (non-recip)
To fornicate means to have sex with someone you are not married to. (FORMAL)
● fornication [N-UNCOUNT]
Fornication is a crime in some American states.