Muck \Muck\, n. [Icel. myki; akin to D. m["o]g. Cf. {Midden}.] 1. Dung in a moist state; manure. --Bacon. 2. Vegetable mold mixed with earth, as found in low, damp places and swamps. 3. Anything filthy or vile. --Spenser. 4. Money; -- in contempt. The fatal muck we quarreled for. --Beau. & Fl. {Muck bar}, bar iron which has been through the rolls only once. {Muck iron}, crude puddled iron ready for the squeezer or rollers. --Knight.