I’m still reading the novel The Abbot by Sir Walter Scott. And—great Scott!—I’m still learning new words!

Heresiarch

A heresiarch is a person who is the originator of heretical doctrine, or a person who is the founder of a sect that sustains such a doctrine. (Wikipedia)

Marplot

A marplot is a person who frustrates or ruins a plan or undertaking by meddling. (Merriam-Webster.com)

Morisco

A morisco was a former Muslim who was forced to convert to Christianity rather than face death or expulsion from Spain. Over time, the term morisco was used pejoratively to refer to nominal Catholics who were suspected of secretly practicing Islam. (Wikipedia)

Runagate

A runagate is a fugitive or runaway and a vagabond or wanderer. (Dictionary.com)

Wanion

The phrase “with a wanion” is equivalent in meaning to the phrases “with a vengeance,” “with a plague,” or “with misfortune.” (The Free Dictionary)

Weasand

A weasand is a throat, esophagus, gullet, trachea, or windpipe. (Dictionary.com)

Yoldring

A yoldring is a species of bunting, which is also called a yellowhammer. (What Does That Mean?) In turn, a bunting is any of several small, chiefly seed-eating birds of the genera Emberiza, Passerina, and Plectrophena. (Dictionary.com)