Maʿānī al-ʾAkhbār > The meaning of haqila, muzabana, ‘araya, mukhabarat, mukhadhara, munabadha, mulamasa, the selling of pebble and other things that were declared forbidden
Hadith #24

وقد قال صلى الله عليه وآله: لقد هممت أن أنهي عن الغيلة. والغيلة هو الغيل وهو أن يجامع الرجل المرأة وهي مرضع. يقال منه: قد أغال الرجل وأغيل ، والولد مغال و مغيل.

He, Allah’s blessings be upon him and his Family, also said: «I have certainly intended to forbid the gheela.» Gheela refers to gheel, and that is when a man has intercourse with a woman while she is breastfeeding. From this it is said of a man: aghal or ugheel. The child is then called mughal and mugheel.