🔼The name Madmen in the Bible
The name Madmen (which has nothing to do with silly guys) occurs only once in the Bible. In his prophecy against Moab, the prophet Jeremiah cries out: "You too, Madmen (מדמן), will be silenced (דמם)," which seems to indicate that Madmen is an otherwise unmentioned town in Moab, but that's not wholly certain (Jeremiah 48:2).
🔼Etymology of the name Madmen
Jeremiah appears to speak of a town in Moab called Madmen, but Isaiah in his prophecy against Moab says: "Moab will be trodden down in his place as straw is trodden down in the water of a מדמנה (madmena" (Isaiah 25:10). It may be that Jeremiah is mentioning a town and Isaiah engages in wordplay, but it's also possible that in the prophets' time Moab had a reputation of being a bit of a cesspool and Jeremiah invents a nickname on the fly.
The "name" Madmen is the masculine variant of the feminine noun מדמנה (madmena), which Isaiah uses, and both derive from the root דמן (dmn), which has to do with manufactured manure:
For a meaning of the name Madmen, both Jones' Dictionary of Old Testament Proper Names and NOBSE Study Bible Name List read Dunghill. BDB Theological Dictionary doesn't offer an interpretation of this name but does list it under the root דמן (dmn).