What is the meaning of うなじや in the following passage?


> 雪乃の汗で濡れ光っている白い **うなじや** 、上衣の合わせ目から覗くほっそりとした鎖骨は、清楚な容貌とは裏腹に淫靡な色香を漂わせている。

what does うなじや mean here ?

> 清楚な容貌とは **裏腹に** 淫靡な色香を漂わせている。

Also what does 裏腹に refer to in this context?




  * うなじや is [うなじ](https://jisho.org/word/%E9%A0%85) ("nape") + や ("and"). うなじ and 鎖骨 are the subjects of the sentence. The simplified version of the sentence is うなじや鎖骨は色香を漂わせている.
  * ～とは裏腹に is an adverbial set phrase, "despite ～", "in contrast to ～", "contrary to ～".

So the sentence is basically saying that although her overall appearance is
clean, her うなじ and 鎖骨 are voluptuous.




  * うなじや is [うなじ](https://jisho.org/word/%E9%A0%85) ("nape") + や ("and"). うなじ and 鎖骨 are the subjects of the sentence. The simplified version of the sentence is うなじや鎖骨は色香を漂わせている.
  * ～とは裏腹に is an adverbial set phrase, "despite ～", "in contrast to ～", "contrary to ～".

So the sentence is basically saying that although her overall appearance is
clean, her うなじ and 鎖骨 are voluptuous.

