mud: [14] The Old English word for ‘mud’ was fen, which now survives only in the sense ‘swamp’. It was replaced in the Middle English period by mud, probably a borrowing from Middle Low German mudde. This goes back ultimately to a prehistoric base *meu-, *mu- that has produced a range of words in the Indo- European languages denoting ‘dirt’ or ‘wet’: Greek múdos ‘damp’, for instance, and Polish muł ‘slime’. Muddle [17] may come from Middle Dutch moddelen ‘make muddy’, a derivative of modde ‘mud’. [mud etymology, mud origin, 英语词源]