no no no no no that is incest
If she has the same natural parents as you have you cannot legally marry her, it would be called incest and it is against the law.
If both are christians I think there is no problem. They are not blood relatives the only relationship they have is through your marriage
Some countrys have strange laws regarding this sort of relationship However as there is no blood relationship there should be no problem in most places.
The children of sisters are first cousins. In most jurisdictions, first cousins can legally marry, but sometimes the family culture or the broader culture of the region frowns on such marriages.
Your mother's sister is you aunt and her husband is your uncle, but his brother (younger or older) is not related to you. If you are an adult female you can marry him if you want, although some religious and cultural groups would find that unacceptable. If you are an adult male you could also marry him, but only in those few places that permit same-sex marriage.
She only has one younger sister Phillipa "Pippa" Middleton. Pippa is not married, but in a relationship.
Mozart married Constanze Weber in 1782, the younger sister of his first love, Aloysia, who had turned him down.
The Maori word for younger sister is "tuahine."
Imouto is for your REAL younger sister and imoutosan for another person's younger sister.
In Lakota, a woman calls her younger sister mithan; a man calls his younger sister thankshi
yh she did fight her sister when she was younger