muck
noun /mʌk/
  /mʌk/
 Idioms - waste matter from farm animals synonym manure
- to spread muck on the fields
 - The tractors are out spreading muck.
 
 - (informal, especially British English) dirt or mud
- Can you wipe the muck off the windows?
 - My face and hands were covered in muck.
 
 - (informal, especially British English) something very unpleasant
- I can't eat this muck!
 
 
Word OriginMiddle English muk, probably of Scandinavian origin: compare with Old Norse myki ‘dung’, from a Germanic base meaning ‘soft’, shared by meek.
Idioms 
where there’s muck there’s brass 
- (British English, saying) used to say that a business activity that is unpleasant or dirty can bring in a lot of money