Film in a shower (4)

I believe the answer is:

scum

(Other definitions for scum that I've seen before include "Impurities floating on surface, or despicable people" , "Fruit of the oak" , "Impurities on surfaces of liquid" , "Floating film of filth" , "Impurities floating on water, or despicable people" .)

I've seen this clue in The Wall Street Journal.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.