distinct vs hard to understand

distinct

adj
  • Separate in place; not conjunct or united; with from. 

  • Different from one another (with the preferable adposition being "from"). 

  • Capable of being perceived very clearly. 

  • Noticeably different from others; distinctive. 

hard to understand

How often have the words distinct and hard to understand occurred in a corpus of books? (source: Google Ngram Viewer )