The phrase "old maxim" refers to a well-known saying or principle that has been around for a long time and has been widely accepted as true or wise. Full definition
Scientists are discovering a huge number of proteins that shape - shift to do their work, upending a century - old maxim of biology. (quantamagazine.org)
Companies» legal counsel and advisers, who perhaps were trained during the cyanide - in - Tylenol days, fall back on old maxims that no longer apply — such as «We will not comment on an ongoing investigation» or «We'll inform the public as soon as when know the complete facts.» (fortune.com)
The decades - old maxim states that you can withdraw 4 % of your nest egg each year after you retire and you'll never run out of money. (moneysense.ca)