Question 1710) - Is Zhihar specific to a comparison with a mother or is it general to any woman one cannot marry?

A: It is general and covers all such women whom one cannot ever marry e.g. sister, paternal aunt, foster-mother etc. If he says, "You are to me as my sister's back/thigh/ vagina,? then it is Zhihar.

~ al-Quduri ~