Fungi and Scum

Fungi noun - The taxonomic kingdom including yeast, molds, smuts, mushrooms, and toadstools; distinct from the green plants.

Scum and fungi are semantically related. in muck topic. In some cases you can use "Scum" instead a noun "Fungi".

Scum noun - People looked down upon as ignorant and of the lowest class.

Fungi and scum are semantically related. Sometimes you can replace term "Fungi" with "Scum", this nouns are similar.