The phrase to put "lipstick on a pig" means making superficial or cosmetic changes to a product in a futile effort to disguise its fundamental failings. There are many phrases using pigs, monkeys, or swine, dating back to biblical times. This phrase seems to have been coined in the 20th century but did not become a common phrase until the 21st century and is often used in politics.
The phrase "lipstick on a pig" has been used for centuries in various forms, including "you can't make a silk purse from a sow's ear." The use of "lipstick on a pig" in its current form dates back to at least 1946, but it gained widespread use in political rhetoric during the 2008 United States presidential election, where it was used to criticize spin and to imply that an opponent (beginning with Sarah Palin) is attempting to repackage established policies and present them as new. It has since been used in political discourse in various countries, sometimes causing controversy.