Where does the phrase “neat but not gaudy” come from?

Solution 1:

The phrase definitely predates Dorothy Sayers (who used the phrase in Whose Body) and Josephine Tey (who used the phrase in Daughter of Time). The Routledge Dictionary of Historical Slang, Eric Partridge, has the following entry for the phrase, and suggests it came into use between 1630 and 1800, the former date also predating Samuel Wesley:

(S.E. = Standard English, c.p. = catchphrase)

Note, Partridge's Dictionary of Catch Phrases has a slightly more-complete entry. It offers a 1700's quote from Samuel Wesley, then quotes “R.C.” to the effect that the original source is Shakespeare's Hamlet, I iii line 75:

Costly thy habit as thy purse can buy,
But not express’d in fancy; rich, not gaudy;

but it seems not clear cut.