"tell it not in Gath" and variants: a proverbial phrase used to discourage the mention of something shameful or discreditable. Earlier also in more general allusive use.
With allusion to the Bible (2 Samuel 1:20): ‘Tell it not in Gath: publish it not in the streetes of Askelon’ (King James).
Mid 16th century; earliest use found in John Bale (1495–1563), bishop of Ossory, evangelical polemicist, and historian. From Gath (Hebrew Gaṯ; goes to post-classical Latin Geth (Vulgate), Hellenistic Greek Γεθ (Septuagint)), the name of a city in ancient Philistia.