idiotism vs polyword

idiotism

noun
  • An overly literal translation of an idiom. 

  • Very severe mental retardation. 

  • A foolish utterance. 

  • Idiom. 

polyword

noun
  • A phrase that acts like a single word. 

How often have the words idiotism and polyword occurred in a corpus of books? (source: Google Ngram Viewer )