Used attributively before nouns, indicating relation to or consisting of scum.
The janitor scrubbed away the scum stains from the tiles.
Le concierge a frotté pour enlever les taches d’écume des carreaux.
Workers removed the scum layer from the scum pond.
Les ouvriers ont retiré la couche écumeuse de l’étang couvert d’écume.
Used attributively before nouns to describe something consisting of or covered with scum, or figuratively to denote something contemptible.