ADAGE, n. A hoary-headed platitude that is kicked along the centuries until nothing is left of it but its clothes. A “saw” which has worn out its teeth on the human understanding.

Ambrose Bierce (1842-1914?) American writer and journalist

“Adage,” “Devil’s Dictionary” column, San Francisco Wasp (1881-03-05)
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Not collected in later books. Instead, in The Cynic's Word Book (1906), he changed it to "Boned wisdom for weak teeth."