guideline vs guidepost

guideline

noun
  • A plan or explanation to guide one in setting standards or determining a course of action. 

  • A light line, used in lettering, to help align the text. 

  • A non-specific rule or principle that provides direction to action or behaviour. 

  • He considered the Ten Commandments more as a guideline than a requirement. 

guidepost

noun
  • Anything that provides guidance; a guideline. 

  • A signpost. 

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