Auto-da-fé

Painting by Francisco Rizi showing an auto-da-fé

It’s Portuguese for “act of faith.”

In most cases, it refers to a series of events during the Inquisitions of the 1500s through the 1800s. These were public punishments and executions of those believed to be heathens or witches. Prisoners were whipped, hanged, or burned at the stake in front of large crowds.

It can be used colloquially to refer to a formal public rebuke, censure, or dressing down of someone.

Why I Looked It Up

From The Real Work:

In Erdnase, you see the same relation between display and deceit that has always been part of magic, only instead of doing things that could get your burned alive at an auto-da-fé he is doing things that could get you shot dead at a card table.

The author is pointing out that this is not “real” magic, but merely card tricks.