(slimy) mud, sludge.
I need to clean the muck off my shirt.
Soft (or slimy) manure.
Anything filthy or vile. Dirt; something that makes another thing dirty.
What's that green muck on the floor?
Grub, slop, swill
Money
The pile of discarded cards.
To shovel muck.
We need to muck the stable before it gets too thick.
To manure with muck.
To do a dirty job.
To pass, to fold without showing one's cards, often done when a better hand has already been revealed.