waifu, wife.
This year again, two Japanese scientist received the Nobel Prize. TV news reports them from various angles. The family life naturally became a popular topic, and interestingly enough, both of them refer to their wives as ワイフ in Japanese. Particularly because the way of their speaking are extremely gentle and polite, their manners made this choice of word stands out.
When I started to learn Japanese, I was told by my teacher that the correct way to refer to one's wife was 家内（かない）. Later, I realized that some one tend to use 妻（つま） in order to avoid the traditional color from such a word. A few years ago, I was surprised to hear my colleague with a high education referred his wife in 奥さん. Now, there is a new variation jointed to this list.