Yennefer Is A Girls Name Of Welsh Origin. This Name Is A Unique Take On The Name Guinevere Which Is Where The Welsh Aspect Comes From. This Name Means "white Fairy", Delivering The Perfect Ethereal Feeling Youve Likely Been Looking For. But Perhaps, The Biggest Claim To Fame For This Name Comes From The Iconic Sorceress In The Witcher Series By Andrjez Sapkowski.