Flagellum and Pest

Flagellum noun - A lash-like appendage used for locomotion (e.g., in sperm cells and some bacteria and protozoa).

Pest and flagellum are semantically related. In some cases you can use "Pest" instead a noun "Flagellum".

Pest noun - A widespread disease resulting in a high rate of death.

Flagellum and pest are semantically related. Sometimes you can replace term "Flagellum" with "Pest", this nouns are similar.