|Origin:||Probably from a Scandinavian language|
dirt, mud, or another sticky substance that makes something dirty:
Come on, let's wipe that muck off your face.
2 British EnglishTADLG
waste matter from animals, sometimes put on land to make plants grow better [= manure]:
special machinery for spreading muck onto the fields
3 British English
something that is unpleasant or of very bad quality:
How can you eat that muck? It looks disgusting.
I'm not surprised she left. He treated her like muck (=very badly).
4 British English informal
to do something very badly and make a lot of mistakes [= muck up]:
I really made a muck of the exam.
5 British English informal
very common or of a low social class