In a certain code language 'who are you' is written as 'Sue Re Nik', 'they is you' is written as 'Pi Re Sor', and 'they are dangerous' is written as 'Pi Nik Zhi'. What is the code for 'dangerous' in that code language?

Zhi

Given; In a certain code language 'who are you' is written as 'Sue Re Nik', 'they is you' is written as 'Pi Re Sor', and 'they are dangerous' is written as 'Pi Nik Zhi'. 

So,

who  are  you  =  sue  re  nik

they  is  you  =  pi  ri  sor

they  are  dangerous  =  pi  nik  zhi

So,

the code for who is sui, are is nik, 'you' is re, 'they' is pi, 'is' is sor, and dangerous is zhi

Thus,

Code for dangerous is zhi