You can call it an aphorism.
A popular maxim or adage is often referred to as a proverb. Proverbs are short, well-known sayings that convey wisdom or a general truth.
It is a PROVERB. :)
Maxim and adage are types of popular sayings.Example:It isn't whether you win or lose that counts, it's how you play the game.Two wrongs don't make a right.What doesn't kill you, only makes you stronger.Where there's a will, there's a way.
adage
Maxim, saying, aphorism.
Some words are proverb, maxim, and saying.
adage, aphorism, byword, maxim, motto, saying
saying, precept, moral, maxim, text, dictum, adage, axiom, motto, byword, proverb
The Personal Maxim (axiom, adage, saying for which he was always known) of Caesar Caligula; "Let them hate me, as long as they fear me"
'Adage' means a saying, a maxim, or proverb. It could also be called a wisdom. So, the antonym foolishness would work. It is also called a truism so falsehoodcould also be an antonym. If you think of it as a cliche, then an uncommon idea would apply.
Clear call check
Adage
"An old adage states that 'laughter is the best medicine,' emphasizing the positive effects of humor on one's well-being."