Coitus with a Woman Illegitimately
Scholars have said that if one dreams of having coitus with a woman in an illicit manner, it may indicate that he is pursuing a matter through improper or unlawful means. This act in a dream may suggest seeking goals from which he will not gain any real or legitimate benefit.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam
Note: These are traditional scholarly interpretations (ijtihad) drawn from a specific classical source — not a binding religious ruling, fortune-telling, or a prediction of the future.