Phrases with the structure 非A非B
"Neither... nor..."
Phrases with the structure 非A非B 
are set expressions that need to be memorized. In the structure, we replace "A" and "B" with words that have similar meanings.
Here are some examples of these set expressions:
非驴非马 (neither ass nor horse)
非亲非故 (neither a relative nor a friend)
非你非我
are set expressions that need to be memorized. In the structure, we replace "A" and "B" with words that have similar meanings.
Here are some examples of these set expressions:
非驴非马 (neither ass nor horse)
非亲非故 (neither a relative nor a friend)
非你非我 Pay attention
In the above structure, "A" and "B" can be replaced with nouns, adjectives or pronouns.
Examples
这座前卫的建筑不适合该地区，非鸦非凤
That avant-garde building is neither fish nor fowl. It’s difficult to classify and not suitable for this area
zhè zuò qiánwèi de jiànzhù bú shìhé gāi dìqū, fēi yā fēi fèng
这部电影的导演非你非我，就是他
The director of this film is neither you nor me. It's him
zhè bù diànyǐng de dǎoyǎn fēi nǐ fēi wǒ, jiù shì tā