Chinese characters for "bu da jie" meaning unrelated
不搭界 (bùdājiè in Mandarin) is a common informal expression in Wu dialects (which include Shanghainese and the Suzhou dialect). Its literal meaning, as indicated in the comments, refers to 'not having a common boundary'. In current usage, it refers to two matters, objects or people having no shared connection or relationship. 

An example, of two people quarrelling:


  A: 阿拉从此浑身不搭界！
  B: 随便侬！
  
  A: We don't have anything to do with each other from now on! (lit: We from now on are unrelated all over the body)
  B: Whatever! (Lit: “Do as you wish”)