counterword vs motto

counterword

noun
  • Such a word (or a word that has gone through a similar change) when not used as a reflex-like answer. 

  • A word (for example so) that is frequently used in a reflex-like manner in an answer and that has thereby quickly taken on a new, much less specific or much looser meaning or is even almost meaningless and performs a completely new function. 

motto

noun
  • A sentence, phrase, or word, forming part of an heraldic achievement. 

  • A sentence, phrase, or word, prefixed to an essay, discourse, chapter, canto, or the like, suggestive of its subject matter; a short, suggestive expression of a guiding principle; a maxim. 

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