guidepost vs guideline

guidepost and guideline both are nouns.

Word	Noun	Adjective	Verb	Adverb
guidepost	Yes	No	No	No
guideline	Yes	No	No	No

As nouns, guidepost and guideline are synonyms defined as:

guidepost and guideline: a rule or principle that provides guidance to appropriate behavior

Other synonyms of guidepost include rule of thumb.

guidepost (noun)	guideline (noun)
a rule or principle that provides guidance to appropriate behavior	a rule or principle that provides guidance to appropriate behavior
a post bearing a sign that gives directions or shows the way	a detailed plan or explanation to guide you in setting standards or determining a course of action
	a light line that is used in lettering to help align the letters