muck potn.†(a) a chamber pot (obsolete);(b) a degraded or degenerate person; cf. muck-spoutn.Sense (b) apparently represents an isolated use by Thomas.
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1557 in M. A. Havinden Househ. & Farm Inventories Oxfordshire (1965) 45 On mucke pott 30.
1938 D. ThomasLet. 6 July in Sel. Lett. (1966) 205 It's a crack at young Georgians,..intellectual muckpots leaning on a theory, post-surrealists and orgasmists.