Scum
Definition 1 of 2
Pro Tip 1/3
Literal meaning
Scum refers to actual physical dirt on liquids like water or soup. You'll need to skim the scum off the top of the boiling broth.
Pro Tip 2/3
Cleaning context
Scum is often mentioned when discussing cleaning fish tanks, ponds, or cooking pots. After the fish tank was cleaned, there was no scum left.
Pro Tip 3/3
Negative perception
When 'scum' refers to dirt, it suggests neglect or unclean conditions. The bathtub is filthy with soap scum.