The Oxford English Dictionary has this definition: “to paint (or to gild) the lily: to embellish excessively, to add ornament where none is needed.”
The phrase is a misquotation from Shakespeare’s King John (1595):
Therefore, to be possess’d with double pomp,
To guard a title that was rich before,
To gild refined gold, to paint the lily,
To throw a perfume on the violet,
To smooth the ice, or add another hue
Unto the rainbow, or with taper-light
To seek the beauteous eye of heaven to garnish,
Is wasteful and ridiculous excess.
That speech in the play expresses King John’s satisfaction with his second coronation. His courtiers aren’t so sure, and said the crowning is ‘superfluous.’
‘To gild’ means to cover with a thin layer of gold, so ‘gilding refined gold’ is quite obviously pointless. Unfortunately, Shakespeare, along with other ancient and not so ancient writers, is often misquoted and, in this case, the words were garbled. As the quotation shows, ‘to paint the lily’ is correct; ‘to gild the lily’ is not.
The term ‘paint the lily’ has the same meaning we now apply to ‘gild the lily.’ Both versions coexisted for a time, although ‘paint the lily’ is now hardly ever used. The first citation for ‘gild the lily’ appears to be from the USA, in the Newark Daily Advocate, 1895, in what seems to be a half-remembered version of Shakespeare:
“One may gild the lily and paint the rose….”
It’s always a temptation to make phrases sound better, and perhaps the misquote happened because of the assonance of the vowels and the alliteration of the ‘l’ in ‘gild’ and ‘lily.’ Certainly the idea of gilding a lily—that is, covering it in gold—is just as outrageous as painting it. However, once the misquotation was committed to print, it would be copied by readers unfamiliar with the speech written by Shakespeare.
I wonder if putting on lipstick could be regarded as gilding the lily. How about tattoos?