To make or become more brown.
To cause to contain more racially 'brown' people, elements, or culture.
To become brown due to increased levels of humic material.
To manure with muck.
To shovel muck.
To vomit.
To do a dirty job.
To pass, to fold without showing one's cards, often done when a better hand has already been revealed.
Heroin.
Semen.
Soft (or slimy) manure.
The pile of discarded cards.
Anything filthy or vile. Dirt; something that makes another thing dirty.
Grub, slop, swill
Slimy mud, sludge.