Maggot

Maggots were small insects and the larvae of flies.

Sometime in the 1970s Global Chemicals dropped chemical waste in Llanfairfach resulting in maggots mutating into giant ones. (TV: The Green Death)

In 2016, the word "maggot" was being used as a derogatory term. Miss Quill used the word against the other Coal Hill defenders (TV: For Tonight We Might Die) and Corakinus used it to insult April MacLean. (TV: Brave-ish Heart)