Adage means a traditional saying or proverb.
Adage is an adjective.
Synonyms: platitude, proverb, saying, aphorism, epigram, maxim, motto, truism.
"Live and let live" is an adage, a saying that has been around for many generations.
The students criticized at the professor's adages, but they always remembered his lessons.
The Principal of the college promised to speak on aggressive new ideas, but his speech consisted of nothing but old ideas and worn-out adages.